Intel storage systems. NAS – network storage system
Information is the driving force of modern business and currently considered the most valuable strategic asset of any enterprise. The volume of information is growing exponentially along with the growth of global networks and development ecommerce. Success in information warfare requires an effective strategy for storing, protecting, sharing, and managing your most important digital asset—data—both today and in the near future.
Managing storage resources has become one of the most pressing strategic issues facing IT departments. Due to the development of the Internet and fundamental changes in business processes, information is accumulating at an unprecedented speed. In addition to the pressing problem of ensuring the possibility of constantly increasing the volume of stored information, the problem of ensuring the reliability of data storage and constant access to information is no less urgent on the agenda. For many companies, the “24 hours a day, 7 days a week, 365 days a year” data access formula has become the norm.
In the case of a separate PC, a storage system (SDS) can be understood as a separate internal hard drive or disk system. When it comes to corporate storage systems, we can traditionally distinguish three technologies for organizing data storage: Direct Attached Storage (DAS), Network Attach Storage (NAS) and Storage Area Network (SAN).
Direct Attached Storage (DAS)
DAS technology involves direct (direct) connection of drives to a server or PC. In this case, storage devices (hard drives, tape drives) can be either internal or external. The simplest case of a DAS system is a single disk inside a server or PC. In addition, a DAS system can also include organizing an internal RAID array of disks using a RAID controller.
It is worth noting that, despite the formal possibility of using the term DAS system in relation to a single disk or an internal array of disks, a DAS system is usually understood as an external rack or basket with disks, which can be considered as an autonomous storage system (Fig. 1). In addition to independent power supply, such standalone DAS systems have a specialized controller (processor) to manage the storage array. For example, such a controller can be a RAID controller with the ability to organize RAID arrays of various levels.
Rice. 1. Example of a DAS storage system
It should be noted that standalone DAS systems can have several external I/O channels, which makes it possible to connect several computers to the DAS system simultaneously.
SCSI (Small Computer Systems Interface), SATA, PATA and Fiber Channel interfaces can be used as interfaces for connecting drives (internal or external) in DAS technology. If SCSI, SATA and PATA interfaces are used primarily for connecting internal drives, then the Fiber Channel interface is used exclusively for connecting external drives and autonomous storage systems. The advantage of the Fiber Channel interface is that in this case in that it does not have a strict length limitation and can be used in cases where the server or PC connected to the DAS system is located at a considerable distance from it. SCSI and SATA interfaces can also be used to connect external storage systems (in this case, the SATA interface is called eSATA), however, these interfaces have a strict limitation on maximum length cable connecting the DAS system and the connected server.
The main advantages of DAS systems include their low cost (compared to other storage solutions), ease of deployment and administration, as well as high speed of data exchange between the storage system and the server. Actually, it is thanks to this that they have gained great popularity in the segment of small offices and small corporate networks. At the same time, DAS systems also have their disadvantages, which include poor controllability and suboptimal utilization of resources, since each DAS system requires the connection of a dedicated server.
Currently, DAS systems occupy a leading position, but the share of sales of these systems is constantly decreasing. DAS systems are gradually being replaced by either universal solutions with the possibility of smooth migration from NAS systems, or systems that provide the possibility of using them both as DAS, NAS and even SAN systems.
DAS systems should be used when it is necessary to increase the disk space of one server and move it outside the chassis. DAS systems can also be recommended for use for workstations that process large volumes of information (for example, for non-linear video editing stations).
Network Attached Storage (NAS)
NAS systems are network storage systems that are directly connected to the network in the same way as a network print server, router or any other network device (Fig. 2). In fact, NAS systems represent an evolution of file servers: the difference between a traditional file server and a NAS device is about the same as between a hardware network router and a software router based on a dedicated server.
Rice. 2. Example of a NAS storage system
To understand the difference between a traditional file server and a NAS device, let's remember that a traditional file server is a dedicated computer (server) that stores information available to network users. To store information, hard drives installed in the server can be used (as a rule, they are installed in special baskets), or DAS devices can be connected to the server. The file server is administered using the server operating system. This approach to organizing data storage systems is currently the most popular in the segment of small local networks, but it has one significant drawback. The fact is that a universal server (and even in combination with a server operating system) is by no means a cheap solution. At the same time, most of the functionality inherent in a universal server is simply not used in a file server. The idea is to create an optimized file server with an optimized operating system and a balanced configuration. This is exactly the concept that a NAS device embodies. In this sense, NAS devices can be considered “thin” file servers, or, as they are otherwise called, filers.
In addition to an optimized OS, freed from all functions not related to file system maintenance and data input/output implementation, NAS systems have a file system optimized for access speed. NAS systems are designed in such a way that all their computing power is focused exclusively on file serving and storage operations. The operating system itself is located in flash memory and is preinstalled by the manufacturer. Naturally, with the release of a new version of the OS, the user can independently “reflash” the system. Connecting NAS devices to the network and configuring them is quite a simple task and anyone can do it experienced user, not to mention the system administrator.
Thus, compared to traditional file servers NAS devices are more powerful and less expensive. Currently, almost all NAS devices are designed for use in Ethernet networks(Fast Ethernet, Gigabit Ethernet) based on TCP/IP protocols. NAS devices are accessed using special file access protocols. The most common file access protocols are CIFS, NFS and DAFS.
CIFS(Common Internet File System System) is a protocol that provides access to files and services on remote computers (including the Internet) and uses a client-server interaction model. The client creates a request to the server to access files, the server fulfills the client's request and returns the result of its work. The CIFS protocol is traditionally used on local networks running Windows OS to access files. CIFS uses the TCP/IP protocol to transport data. CIFS provides functionality similar to FTP ( File Transfer Protocol), but provides clients with improved control over files. It also allows you to share file access between clients using blocking and automatic recovery connection with the server in case of network failure.
Protocol NFS (Network File System - network file system) is traditionally used on UNIX platforms and is a combination of a distributed file system and a network protocol. The NFS protocol also uses a client-server communication model. The NFS protocol allows files on a remote host (server) to be accessed as if they were on the user's computer. NFS uses the TCP/IP protocol to transport data. To operate NFS on the Internet, the WebNFS protocol was developed.
Protocol DAFS(Direct Access File System) is a standard file access protocol that is based on NFS. This protocol allows application tasks to transfer data bypassing the operating system and its buffer space directly to transport resources. The DAFS protocol provides high file I/O speeds and reduces processor load by significantly reducing the number of operations and interrupts that are typically required during processing network protocols.
DAFS was designed with a focus on use in cluster and server environments for databases and a variety of Internet applications focused on continuous work. It provides the lowest latency for accessing file shares and data, and also supports intelligent system and data recovery mechanisms, which makes it attractive for use in NAS systems.
Summarizing the above, NAS systems can be recommended for use in multi-platform networks when network access to files is required and sufficient important factors are ease of installation and storage system administration. An excellent example is the use of a NAS as a file server in the office of a small company.
Storage Area Network (SAN)
Actually, SAN is no longer a separate device, but a comprehensive solution, which is a specialized network infrastructure for data storage. Storage networks are integrated as separate specialized subnets into a local (LAN) or wide area (WAN) network.
Essentially, SANs connect one or more servers (SAN servers) to one or more storage devices. SAN networks allow any SAN server to access any storage device without burdening other servers or the local network. In addition, it is possible to exchange data between storage devices without the participation of servers. In fact, SANs allow a very large number of users to store and share information in one place (with fast, centralized access). RAID arrays, various libraries (tape, magneto-optical, etc.), as well as JBOD systems (disk arrays not combined into RAID) can be used as data storage devices.
Data storage networks began to develop intensively and be implemented only in 1999.
Just as local networks can, in principle, be built on the basis of various technologies and standards, various technologies can also be used to build SAN networks. But just as the Ethernet standard (Fast Ethernet, Gigabit Ethernet) has become the de facto standard for local area networks, the Fiber Channel (FC) standard dominates in storage networks. Actually, it was the development of the Fiber Channel standard that led to the development of the SAN concept itself. At the same time, it should be noted that the iSCSI standard is becoming increasingly popular, on the basis of which it is also possible to build SAN networks.
Along with speed parameters, one of the most important advantages Fiber Channel is capable of operating over long distances and has topology flexibility. The concept of building a storage network topology is based on the same principles as traditional local networks based on switches and routers, which greatly simplifies the construction of multi-node system configurations.
It is worth noting that the Fiber Channel standard uses both fiber optic and copper cables to transmit data. When organizing access to geographically remote nodes at a distance of up to 10 km, standard equipment and single-mode optical fiber are used for signal transmission. If the nodes are separated over a greater distance (tens or even hundreds of kilometers), special amplifiers are used.
SAN network topology
A typical SAN network based on the Fiber Channel standard is shown in Fig. 3. The infrastructure of such a SAN network consists of storage devices with a Fiber Channel interface, SAN servers (servers connected both to the local network via an Ethernet interface and to the SAN network via a Fiber Channel interface) and a switching fabric (Fiber Channel Fabric) , which is built on the basis of Fiber Channel switches (hubs) and is optimized for transmitting large blocks of data. Access network users to the data storage system is implemented through SAN servers. It is important that the traffic inside the SAN network is separated from the IP traffic of the local network, which, of course, makes it possible to reduce the load on the local network.
Rice. 3. Typical SAN network diagram
Advantages of SAN networks
The main advantages of SAN technology include high performance, high level of data availability, excellent scalability and manageability, and the ability to consolidate and virtualize data.
Fiber Channel switch fabrics with a non-blocking architecture allow multiple SAN servers to simultaneously access storage devices.
With a SAN architecture, data can easily move from one storage device to another, allowing for optimized data placement. This is especially important when multiple SAN servers require simultaneous access to the same storage devices. Note that the process of data consolidation is not possible when using other technologies, such as, for example, when using DAS devices, that is, data storage devices directly connected to servers.
Another opportunity provided by SAN architecture is data virtualization. The idea of virtualization is to provide SAN servers with access not to individual storage devices, but to resources. That is, servers should “see” not storage devices, but virtual resources. For practical implementation of virtualization between SAN servers and disk devices a special virtualization device can be placed, to which storage devices are connected on one side, and SAN servers on the other. In addition, many modern FC switches and HBAs provide the ability to implement virtualization.
The next opportunity provided by SAN networks is the implementation of remote data mirroring. The principle of data mirroring is to duplicate information on several media, which increases the reliability of information storage. An example of the simplest case of data mirroring is combining two disks into a RAID level 1 array. In this case, the same information is written simultaneously to two disks. The disadvantage of this method is the local location of both disks (as a rule, the disks are located in the same basket or rack). Storage networks allow you to overcome this drawback and provide the opportunity to organize mirroring not just of individual data storage devices, but of the SAN networks themselves, which can be hundreds of kilometers away from each other.
Another advantage of SAN networks is the ease of organizing data backup. Traditional technology backup, which is used in most local networks, requires a dedicated Backup server and, most importantly, dedicated network bandwidth. In fact, during the backup operation, the server itself becomes unavailable to local network users. In fact, this is why backups are usually performed at night.
The architecture of storage networks allows us to approach the problem of backup in a fundamentally different way. In this case, the Backup server is part of the SAN network and is connected directly to the switching fabric. In this case, Backup traffic is isolated from local network traffic.
Equipment used to create SAN networks
As already noted, deploying a SAN network requires storage devices, SAN servers, and equipment to build a switch fabric. Switching fabrics include both physical layer devices (cables, connectors) and connection devices (Interconnect Device) for connecting SAN nodes with each other, translation devices (Translation devices) that perform the functions of converting the Fiber Channel (FC) protocol to other protocols, for example SCSI, FCP, FICON, Ethernet, ATM or SONET.
Cables
As already noted, the Fiber Channel standard allows the use of both fiber optic and copper cables to connect SAN devices. At the same time, different types of cables can be used in one SAN network. Copper cable is used for short distances (up to 30 m), and fiber optic cable is used for both short and distances up to 10 km or more. Both Multimode and Singlemode fiber optic cables are used, with Multimode used for distances up to 2 km, and Singlemode for longer distances.
Coexistence various types cables within the same SAN network are provided using special interface converters GBIC (Gigabit Interface Converter) and MIA (Media Interface Adapter).
The Fiber Channel standard has several possible transmission rates (see table). Note that currently the most common FC devices are standards 1, 2 and 4 GFC. This ensures backward compatibility of faster devices with slower ones, that is, a 4 GFC device automatically supports connecting devices of 1 and 2 GFC standards.
Interconnect Device
The Fiber Channel standard allows the use of various network topologies device connections such as Point-to-Point, Arbitrated Loop (FC-AL) and switched fabric.
A point-to-point topology can be used to connect a server to a dedicated storage system. In this case, the data is not shared with the SAN servers. In fact, this topology is a variant of a DAS system.
To implement a point-to-point topology, at a minimum, you need a server equipped with a Fiber Channel adapter and a storage device with a Fiber Channel interface.
The split-access ring topology (FC-AL) refers to a device connection scheme in which data is transferred logically closed loop. In an FC-AL ring topology, the connection devices can be hubs or Fiber Channel switches. With hubs, the bandwidth is shared among all nodes in the ring, while each switch port provides protocol bandwidth to each node.
In Fig. Figure 4 shows an example of a split Fiber Channel ring.
Rice. 4. Example of a Fiber Channel ring with shared access
The configuration is similar to the physical star and logical ring used in local area networks based on Token Ring technology. Also, like Token Ring networks, data travels around the ring in one direction, but unlike Token Ring networks, a device can request permission to transmit data rather than wait for an empty token from the switch. Fiber Channel rings with shared access can address up to 127 ports, however, as practice shows, typical FC-AL rings contain up to 12 nodes, and after connecting 50 nodes, performance deteriorates catastrophically.
The topology of the switched communication architecture (Fiber Channel switched-fabric) is implemented on the basis of Fiber Channel switches. In this topology, each device has a logical connection to every other device. In fact, Fiber Channel fabric switches perform the same functions as traditional Ethernet switches. Recall that, unlike a hub, a switch is a high-speed device that provides “everyone-to-everyone” connectivity and handles multiple simultaneous connections. Any node connected to a Fiber Channel switch receives protocol bandwidth.
In most cases, when creating large SAN networks, a mixed topology is used. At the lower level, FC-AL rings are used, connected to low-performance switches, which, in turn, are connected to high-speed switches, providing the highest possible throughput. Multiple switches can be connected to each other.
Broadcast devices
Translation devices are intermediate devices that convert the Fiber Channel protocol to higher-level protocols. These devices are designed to connect a Fiber Channel network to an external WAN network, a local network, as well as to connect various devices and servers to a Fiber Channel network. Such devices include bridges, Fiber Channel adapters (Host Bus Adapters (HBA), routers, gateways and network adapters. The classification of broadcast devices is shown in Fig. 5.
Rice. 5. Classification of broadcast devices
The most common translation devices are HBA adapters with a PCI interface, which are used to connect servers to a Fiber Channel network. Network adapters allow you to connect local Ethernet networks to Fiber Channel networks. Bridges are used to connect storage devices with SCSI interface to a Fiber Channel-based network. It should be noted that recently almost all data storage devices that are intended for use in SANs have built-in Fiber Channel and do not require the use of bridges.
Storage devices
Both hard drives and tape drives can be used as data storage devices in SAN networks. If we talk about possible configurations for using hard drives as data storage devices in SAN networks, these can be either JBOD arrays or RAID disk arrays. Traditionally, storage devices for SAN networks are produced in the form of external racks or baskets equipped with a specialized RAID controller. Unlike NAS or DAS devices, devices for SAN systems are equipped with a Fiber Channel interface. At the same time, the disks themselves can have both a SCSI and SATA interface.
In addition to hard drive-based storage devices, tape drives and libraries are widely used in SAN networks.
SAN servers
SAN servers differ from conventional application servers in only one detail. In addition to the Ethernet network adapter, for the server to interact with the local network, they are equipped with an HBA adapter, which allows them to be connected to SAN networks based on Fiber Channel.
Intel Storage Systems
Next we will look at several specific examples Intel storage devices. Strictly speaking, Intel does not produce complete solutions and is engaged in the development and production of platforms and individual components for building data storage systems. Based on these platforms, many companies (including a number of Russian companies) produce complete solutions and sell them under their logos.
Intel Entry Storage System SS4000-E
The Intel Entry Storage System SS4000-E is a NAS device designed for use in small and medium-sized offices and multi-platform local area networks. When using the Intel Entry Storage System SS4000-E, clients based on Windows, Linux, and Macintosh platforms receive shared network access to data. In addition, the Intel Entry Storage System SS4000-E can act as both a DHCP server and a DHCP client.
The Intel Entry Storage System SS4000-E is a compact external rack with the ability to install up to four SATA drives (Fig. 6). Thus, the maximum system capacity can be 2 TB using 500 GB drives.
Rice. 6. Intel Entry Storage System SS4000-E
The Intel Entry Storage System SS4000-E uses a SATA RAID controller that supports RAID levels 1, 5, and 10. Because this system is a NAS device, that is, in fact, a “thin” file server, the data storage system must have a specialized processor, memory and a firmware operating system. The processor in the Intel Entry Storage System SS4000-E uses an Intel 80219 with clock frequency 400 MHz. In addition, the system is equipped with 256 MB DDR memory and 32 MB of flash memory for storing the operating system. The operating system is Linux Kernel 2.6.
To connect to a local network, the system provides a two-channel gigabit network controller. In addition, there are also two USB ports.
The Intel Entry Storage System SS4000-E data storage device supports CIFS/SMB, NFS and FTP protocols, and the device is configured using a web interface.
In the case of using Windows clients (Windows 2000/2003/XP are supported), it is additionally possible to implement data backup and recovery.
Intel Storage System SSR212CC
The Intel Storage System SSR212CC is a universal platform for creating DAS, NAS and SAN storage systems. This system is housed in a 2 U high housing and is designed for mounting in a standard 19-inch rack (Fig. 7). The Intel Storage System SSR212CC supports installation of up to 12 drives with SATA or SATA II interface (hot-swappable) which allows you to expand the system capacity up to 6 TB using 550 GB drives.
Rice. 7. Intel Storage System SSR212CC
In fact, the Intel Storage System SSR212CC is a full-fledged high-performance server running operating systems Red Hat Enterprise Linux 4.0, Microsoft Windows Storage Server 2003, Microsoft Windows Server 2003 Enterprise Edition and Microsoft Windows Server 2003 Standard Edition.
The server is based on an Intel Xeon processor with a clock frequency of 2.8 GHz (FSB frequency 800 MHz, L2 cache size 1 MB). The system supports the use of SDRAM DDR2-400 memory with ECC with a maximum capacity of up to 12 GB (six DIMM slots are provided for installing memory modules).
The Intel Storage System SSR212CC is equipped with two Intel RAID Controller SRCS28Xs with the ability to create RAID arrays of levels 0, 1, 10, 5 and 50. In addition, the Intel Storage System SSR212CC has a dual-channel gigabit network controller.
Intel Storage System SSR212MA
The Intel Storage System SSR212MA is a platform for creating data storage systems in IP SAN networks based on iSCSI.
This system is housed in a 2 U high housing and is designed for mounting in a standard 19-inch rack. The Intel Storage System SSR212MA supports installation of up to 12 SATA drives (hot-swappable), allowing system capacity to be expanded up to 6 TB using 550 GB drives.
In terms of its hardware configuration, the Intel Storage System SSR212MA is no different from the Intel Storage System SSR212CC.
NAS (Network Attached Storage) is a network data storage system. Network storage is an external hard disks, which connect to a network and allow multiple users to work with shared files. NAS is becoming more and more popular, which, in general, is not surprising. The volume of stored information increases exponentially from year to year, and accordingly, the market for NAS systems does not stand still, as IDC has repeatedly noted in its forecasts.
In today's material we want to talk a little more about the network storage system - NAS.
File server or NAS?
Network Attached Storage provides for connecting information storage devices directly to a computer network. It is worth noting that the network storage system operates both in local and distributed networks, the main thing is that there is a TCP/IP protocol and Ethernet technology.
A more or less prepared reader will have quite reasonable questions: why NAS? Where did the file server go?
The fact is that often in the enterprise infrastructure the server performs a number of functional tasks, which directly affects the speed direct access to data and, as a result, causes a heavy load on the system as a whole. Add questionable flexibility - if the server fails, you simply have no access to the data. Yes, and increasing the capacity of a serious server costs a lot of money, and it is not uncommon for the server to physically not have enough space for the next addition of hard drives.
Network-attached storage is more flexible in this regard and is friendlier to the consumer's wallet.
NAS architecture
The NAS architecture is maximally optimized for a specific task: file service. The design of NAS products is based on a key rule: all computing power is concentrated on the single and main task - serving and storing files. By limiting yourself to a key task, NAS products allow you to organize the work of a group of users with shared files as efficiently as possible in terms of speed and costs.
The flexibility of Network Attached Storage is excellent: simple and convenient administration, the ability to increase volume without shutting down the main system, the use of standard communication protocols and network connections. Connecting NAS devices to the network does not require any specific interfaces or special hardware. It is enough to connect Network Attached Storage to the network, and all its resources become available to users whose NAS appears in the form of additional disks. Such simple opportunities for increasing data storage capacity will be appreciated by companies with a serious computer infrastructure.
The network storage system uses simplified operating systems; such OSs are stripped of all unnecessary services and modules and at the same time are maximally optimized for serving the file system. The simple architecture of the software allows for high data transfer speeds and the fastest possible response to user requests, without requiring any serious computing power. As a rule, such OSes are hardwired into the device’s flash memory and pre-installed by the manufacturer, but there is also software that is freely distributed on the Internet. We will talk about one such operating system below.
Summarizing everything written above, we can say with confidence that the NAS architecture allows you to get an incredibly attractive cost per gigabyte of data storage, network storage systems do not require serious administration, work with any platform (Windows, Linux, etc.), and do not require any or specific interfaces and are distinguished by convenient and simple process increasing disk space.
The development of Ethernet technology and the emergence of gigabit networks have significantly increased the performance of NAS systems and, as a result, increased the attractiveness of such solutions. Today various manufacturers offer their NAS solutions. Thanks to such a flexible NAS architecture, manufacturing companies are able to satisfy the needs of all price segments - from the needs of a serious corporation to the tasks of a small home infrastructure, the concept of a “digital home”.
Digital home
Digital home
NAS products have another undeniable advantage - accessibility. If you are a home network administrator and do not have serious finances, or simply want to have Network Attached Storage and do not want to spend a large amount of money, then you can build a network storage system based on the FreeNAS operating system.
FreeNAS
The FreeNAS operating system is based on the BSD kernel, which is highly optimized for Network Attached Storage tasks. FreeNAS itself takes up a minimal amount of disk space (42 MB) and allows you to boot from a CD or a flash drive.
FreeNAS is managed and configured using a simple web interface. Everything is as simple as possible: we assemble a regular budget PC with a network card, install the required number of hard drives, insert a CD with FreeNAS, making sure in advance that BIOS Setup The “Boot from CD” option is enabled on the motherboard. Load up and get ready working system data storage, to configure which we just need to enter the server’s IP address in the browser (in order to find out the IP address, we will have to connect the monitor to our Network Attached Storage), and then the username and password (by default it is admin/freenas).
conclusions
Summarizing all of the above, we can safely say that Network Attached Storage are quite interesting and promising data storage solutions. NAS products have a lot of advantages: availability, flexibility, convenience and ease of setup. All these are strong arguments in favor of networked storage systems. The prospects of NAS are evidenced not only by its strengths, but also by the numbers. The Network Attached Storage market is constantly evolving, and, according to IDC reports, there is significant growth in this segment.
We will definitely continue the topic of Network Attached Storage and in the near future we will introduce you, dear readers, to the practical component of network storage systems or, in simple terms, we will build a budget, affordable NAS system using inexpensive components and the FreeNAS operating system.
NAS (Network Attached Storage) technology is developing as an alternative universal servers. Unlike servers, NAS devices perform only one function - file storage of data. By design, a NAS is a specialized cacheable server that connects directly to a local area network (LAN), typically using Ethernet, providing access to pre-configured storage space using its own integrated file system and data management software, to an unlimited number of heterogeneous clients or other servers .
Thus, NAS can be considered a complete solution in the field of data storage, a very reliable and stable solution with a low price. In most cases, NAS is the optimal solution for small companies and allows you to create a capacious information storage network with little cost.
Unlike servers, NAS devices perform only one function - file storage of data. By design, a NAS is a specialized cacheable server that connects directly to a local area network (LAN), typically using Ethernet, providing access to pre-configured storage space using its own integrated file system and data management software, to an unlimited number of heterogeneous clients or other servers . The NAS device is quick solution problems of lack of free disk space, because After connecting the NAS device to the computer network, you can start working with it almost immediately.
NAS device is a quick solution to the problem of lack of free disk space, because... After connecting the NAS device to the computer network, you can start working with it almost immediately.
By design, a NAS is a specialized cacheable server that connects directly to a local area network (LAN), typically using Ethernet, providing access to pre-configured storage space using its own integrated file system and data management software, to an unlimited number of heterogeneous clients or other servers .
NAS networks are best suited for small offices or departments of enterprises. Systems of this type are quite simple to administer. NAS devices, in common terminology, are plug-and-play devices. They connect to an existing local area network (LAN), determine their own IP addresses, and then appear on the network as additional drives information. Due to the fact that NAS devices perform only strictly limited functions, they often use either special operating systems or standard OSes with limited functionality, and this allows the use of inexpensive embedded processors with small volumes RAM, because they are spent only on storing and retrieving data.
In addition, NAS devices are multi-protocol, that is, they support several network file system protocols, such as NFS (UNIX), CIFS (Windows), and HTTP (iSCSI) to create a geographically distributed storage network using the Internet.
If we talk about the disadvantages of NAS, then, no matter how strange it may sound, they are a direct consequence of the advantages.
Since Network Attached Storage connects directly to the existing LAN, there is a problem such as data transit between the NAS server and application servers (or client PCs). end users). In other words, heavy use of a NAS significantly reduces bandwidth and overloads the network.
NAS devices can be the simplest “boxes” with one Ethernet port and two hard drives in RAID-1, allowing access to files using only one protocol such as CIFS (Common Internet File System),
to huge systems in which hundreds of hard drives can be installed, and file access is provided by dozens of specialized servers inside the NAS device.
The number of external Ethernet ports can reach many dozens, and the capacity of stored data is several hundred terabytes.
One of the purposes of NAS devices is to work in a heterogeneous environment where fast file access to data is required for many clients simultaneously.
It also provides excellent storage reliability and system management flexibility coupled with ease of maintenance.
As for the heterogeneous environment, access to files within a single NAS system can be obtained using protocols such as TCP/IP, CIFS, NFS, FTP, TFTP, which ensures operation with various operating systems installed on the host servers .
As for ease of maintenance and flexibility of management, these capabilities are provided by a specialized OS, which is difficult to disable and does not need to be maintained, as well as the ease of delimiting access rights to files. For example, it is possible to work in a Windows environment Active Directory with support for the required functionality - this could be LDAP, Kerberos Authentication, Dynamic DNS, ACLs, assignment of quotas (quotas), Group Policy Objects, etc. Because the NAS device provides access to files, and the names of these files may contain the characters different languages, many NAS devices provide support for UTF-8, Unicode encodings.
The choice of NAS devices should be approached even more carefully than other storage devices, because... Such hardware may not support the services you require, such as Microsoft's Encrypting File Systems (EFS) and IPSec.
The main advantages of NAS devices:
Simplicity and ease of installation and administration;
. relatively low cost;
. support for access restriction standards;
. versatility for clients (Microsoft Winodws, Novell, Mac, Unix, Linux);
. support for most backup programs;
. the ability to access data in case of failure of the main server;
. storing a large amount of various information.
Thus, NAS can be considered a complete solution in the field of data storage, a very reliable and stable solution with a low price. In most cases, NAS is the optimal solution for small companies and allows you to create a capacious information storage network with little cost.
The amount of information stored on our computers is increasing every day. Thousands of photos musical recordings, hundreds of films and TV series - all this is destroying free space on your computer at an insane speed. hard drives x of our computers. It’s not always possible to buy and install another HDD suitable solution, because there may simply not be enough space in the PC case, especially if you have a laptop. Using external hard drives is often inconvenient to use – take it out, connect it, etc. We would like to access the photo or music composition we need without fiddling with wires, or simultaneously from different devices on your network. And in such a situation, network data storages can come to the rescue.
Storage units without storage media included are suitable for home use, especially if you have already purchased disks.
When used in small offices, pay attention to more reliable and functional network storage. As a rule, such NAS are supplied without storage media and are equipped with two network interfaces and more powerful hardware to cope with high loads.
Definition of characteristics
The main aspect of choosing a NAS is the total volume, which is based on the capacity of the drives and their number. To determine the volume, you need to consider:
- An array of information for transfer to network storage, information on all devices on your network;
- The approximate volume you will record over the next couple of years.
The optimal solution for home use is network storage with a capacity of 4 – 6 TB. This is guaranteed to be enough for both backup from 2-3 computers and for storing multimedia files.
Are you a professional photographer or just a passionate amateur? Then you definitely cannot do without network storage for storing your work and for backing up the material you have just shot and not yet processed. Believe me, cases of losing photos due to hard drive failure are not uncommon, and the lack of a backup copy will put an end to the entire work of the photographer’s team. So network storage with a capacity of 6-8 TB is an excellent solution for storage and backup.
The number of installed drives affects not only the maximum amount of network storage, but also the ability to create RAID arrays to provide increased productivity or fault tolerance. For example, support for RAID 1 (mirrored) or RAID 5 will help protect against data loss. In the first case, the network storage requires at least two hard drives (the volume of the disk system available to the user will be equal to the capacity of one disk), and in the second case, at least three disks (also, part of the disk space will be allocated for service needs). This configuration allows you to save information if one of the disks fails.
Software features
Owners of smart TVs will find the UPnP/DLNA server function useful for viewing media content without the need to save it on the device.
Network-attached storage can be used not only as a large hard drive connected to the network. Separate devices allow you to install additional applications, for example a torrent tracker, various download managers, dropbox, etc. This will greatly expand the capabilities of your NAS.
Another interesting feature of network storage is support for IP video surveillance for organizing a video archive and will eliminate the need to purchase a separate DVR.
Results
Choosing a network storage can be reduced to a few simple steps:- Do I need a storage device included in the kit? If so, is one sufficient, or are two or more needed to provide greater capacity or increased fault tolerance?
- Determine the amount of disk space you need
- Determine what additional functions and tasks the network storage will perform and make sure that they are available in the selected samples.
Part One: Cold Iron
It can be stewed and chopped into broth,
And it's good to serve with vegetables.
Lewis Carroll, The Hunting of the Snark
Anyone who can collect Personal Computer and install Windows, if desired, it can also cope with the creation of a fairly advanced NAS from x86-compatible hardware and free software assemblies based on *nix. In this case, roughly speaking, the number installed disks affects the cost and labor intensity of the project only by the cost of the disks. This allows you to seriously save money compared to buying a ready-made NAS with 4 or more disks, but it is hardly profitable if a NAS with 1-2 disks satisfies your needs. It is impossible to say which option is better. Everyone has their own preferences. Some people cook well at home, while others prefer to dine in a restaurant. Do you enjoy tinkering with computer software and hardware? Then this text may be useful. Do you need a storage service on its own? Choose between cloud storage and a ready-made NAS out of the box.
N. B. This article is not about the equipment model or version software product. It's about the concept creating a NAS with your own hands and suggests considering other options for solving the problem, besides purchasing a ready-made device. The topic is long, with nearly a thousand pages of discussion. The people there are polite and responsive. This is a hint that the article does not pretend to be complete, academic or the ultimate truth.
What kind of NAS is this?
According to Wikipedia, NAS (Network Attached Storage) - network storage system, network storage. It is a computer connected to a network and designed to provide data storage services to other devices. The operating system and NAS module programs provide operation of the data storage and file system, access to files, and control over system functions. The device is not designed to perform normal computing tasks, although running other programs on it may be technically possible. Typically, NAS devices do not have a screen or keyboard, but are managed and configured over the network, often using a browser.
The definition is not ideal, but quite working. NAS is also used in business, but they have their own requirements and features. We will be interested in home use of NAS.
People usually come to the idea of assembling a NAS with their own hands in two ways, and often in both ways at once. When you have one computer at home, you don't need a NAS. Gradually other network devices appear. Laptops, smartphones, tablets. And especially - network HD media players, all sorts of Dune, Popcorn, WD TV and the like. It is with the acquisition of a network media player that a person often begins to accumulate terabytes of information. It is first stored on removable hard drives that are connected to the media player and/or added to the main computer. Soon there will be too many disks for convenient use, and a computer quietly buzzing around the clock, at the same time downloading something from the Internet, will begin to irritate, if not you, then your better half. An idea arises to collect this bunch of disks in a separate box, put it somewhere in a corner and instruct it to distribute content to all network devices and download torrents. Congratulations, you've taken the first route to NAS. On the way, we definitely took a look at the finished NAS, out of the box. But the price!..
The second way is through hardware upgrades. As a result, less than a cubic meter of components accumulate, which are difficult to sell and there is no one to give as a gift. The Plyushkin within us finds a useful use for them in the idea of building a NAS. And at the same time satisfy your craving to rummage through the guts of the computer. It’s not for nothing that one cheerful American wrote that working with a computer is the only legal way today to push around someone who is smarter than you.
Of course, there are other ways. For example, you are a keen photographer and need reliable storage of long-term archives. Or a loving parent filming every step of their baby. Etc. But rarely do such scenarios lead to assembling a NAS with your own hands. Much more often - to buy ready-made out of the box. The needs of such users are confidently met by 1-2 disk models of ready-made NAS. Assemble something similar in size, noise and price yourself 1-2 disk models It is difficult, if not impossible, for a neophyte amateur.
In defense of ready-made NAS, it is worth noting that they provide many features and functions out of the box, requiring minimal installation/configuration/tuning. So, in fact, their cost must also include the work of programmers, technical support etc.
The situation changes dramatically if 1-2 disks are not enough, but there is a need for 4 or more. Manufacturers' marketers install on them price level, which plunges a person familiar with a computer price tag into a state of frustration (although they pronounce much more popular words). And the person begins to choose a hardware configuration, to which we move on. Although he should have started with software, he can’t go against nature.
The hardware depends on the software used. Software - depending on the assigned tasks. And the correct formulation of the problem has never been a strong point of the home handyman. So he starts with hardware. If we came to building a NAS with a bag of parts left over from upgrades, then the good news is that they will fit, even if not optimally. Without even looking.
Broomed around the barn
In order to comfortably watch FullHD video over the network, including BD disk images, we will need at least:
- 1-2 gigabytes of RAM if ZFS is not used and 4-8, more is possible if ZFS is used. (About ZFS - later, Google will help the impatient.) But even on a rarity with 256 MB you can collect something useful;
- x86-compatible processor, ideally (and for ZFS) - 64-bit, but 32-bit is suitable for most options. That is, any x86 processor except those that are completely museum-quality. It would be preferable to have less heat, but that’s what it is;
- wired Ethernet port, preferably gigabit - although 100 megabits is enough for viewing BD images over the network. Connecting a NAS over Wi-Fi is a controversial idea (but if you build it yourself, you have much more more freedom in choosing wireless controllers);
- drives and SATA ports. For NAS there is no difference between SATA-2 (3 Gbit/s) and SATA-3 (6 Gbit/s). Not every drive is faster than the ancient SATA-1, so such ports can be used. But IDE drives, by modern standards, are slow, low-capacity, hot and noisy. If there are not enough SATA ports, you can use controllers. But if (when) you soon decide to move to new hardware, then the SATA controllers purchased as crutches for an outdated motherboard will lie idle. I know from myself, I have two lying around. And be careful with disks larger than 2 TB. Many older controllers are not compatible with them. And among the SATA-1 controllers, there are also those that do not work with disks larger than a terabyte - however, this is already ancient and rare;
- Of course, the case where it will all fit and the power supply that will pull it. There are subtleties with the power supply, it makes sense to look at a new one, see below.
Most likely, the hardware left over from the upgrades will satisfy these requirements. And if it doesn’t make much noise (or there is somewhere to clean it), then you’re generally lucky. You can start experimenting.
Custom tailoring
If you are assembling a NAS from specially purchased components, then you should first decide on your wishes. In most cases (but it is impossible to grasp the immensity) requests are divided into three groups, conventionally “quiet-compact”, “effective-extensible” and “server-so-server”. Let me clarify that there is no clearly correct option. After all, the user himself weighs wishes, costs and his capabilities. But the wrong one is possible. When the result does not satisfy the requirements explicitly or implicitly specified during the design. For example, the spouse will say that the box is, of course, big. But it howls like an airplane, and she doesn’t agree to live in the same apartment. Or the system assembled under passive conditions does not withstand the test in the summer. Or the video simply shuts down when viewed online. Therefore, it is better to consider your wishes on the shore. Especially the implicit ones.
Important note. We're talking about a NAS, not an HTPC (Home Theater PC), that is, not a computer that shows movies with sound on a large screen connected to its video output. In principle, no one forbids you to make HTPC, including with many hard drives, although the requirements for HTPC and NAS, as well as the software and hardware used for them, are very different. HTPC is a different topic.
Quietly compact
This set of requirements is influenced by off-the-shelf NAS. I want something compact and quiet, but one that can fit 4 disks (often 6, sometimes more). Such requirements usually lead to the choice of a Mini-ITX motherboard with a soldered Atom-like processor housed in a compact case. Examples are below.
There is a very good preconfigured solution - HP Proliant Microserver (). Compact, reasonable in price (from 12,000 at the moment), 4 hard drives, the fifth can be inserted instead of ODD, which is unnecessary in the NAS. And with the help of a small tambourine, make the port intended for ODD SATA work normally. Disadvantages - far from powerful processor, but for many scenarios it is sufficient. If you are satisfied with the microserver, let's go to the chapter about software.
HP Proliant Microserver is a high-quality and inexpensive candidate for the role of home NAS
If not, first select a case for the desired number of disks (whether or not a disk is needed for the system depends on the OS. We will discuss it in the chapter about software). Here, in the battle of show-off aesthetic feelings with greed and the desire for effective costs, the first test of the strength of the “quiet-compact” concept takes place. Beautiful compact cases are not cheap. If victory lies with the toad's desire for efficiency, let's go to the chapter on efficiency and extensibility. We go there if the selected case allows the installation of a microATX motherboard. If aesthetics win, we select a Mini-ITX (Mini-DTX) motherboard. The first requirement is a maximum of SATA ports (including eSATA). In principle, desktop versions with 6 SATA ports were produced. But whether it will be possible to find it here and now is the question. If there are not enough ports, PCIe SATA controllers with 2 and even 4 ports are quite affordable. Naturally, they require a PCIe slot. Considering that it is the only one in Mini-ITX, expandability ends there.
Examples all from real life, often with modifications and additional photos - see FAQ in the profile thread, section 3.1
| by axel77 | from half_moon_bay | by padavan | |
| Frame | Chenbro ES34069 | Lian Li PC-Q25 | Lian-Li PC-Q08 |
| power unit | 180 W included | Corsair, PSU-500CXV2EU, 500 W | Enermax 380 W (82+) |
| Motherboard | Zotac NM10-DTX WiFi | Asus E35M-I* | Asus P8H67-I** |
| CPU | integrated Intel Atom D510 | integrated AMD E-350 | Intel Pentium G840 |
| RAM | Kingston 2x2 GB | Corsair XMS3 2x8 GB | 2x4 GB DDR3-1333 |
| Hard drives for data | 4×Samsung HD204UI | 7×3.5″ | 6×3.5″ + hotswap for 3.5″ HDD in 5.25″ bay |
| System storage | 2.5″ Toshiba 500 GB | USB flash drive | 2.5″ HDD |
| operating system | FreeBSD | FreeNAS 8.x | OMV |
| Additionally | network Intel WG82574L*** | ST-Lab 370 4xSATA | PCIe 2xSATA-II |
| Price estimate**** | RUB 14,950 | RUB 15,600 | RUB 14,000 |
* Nowadays motherboards with E-350 have become rare, they have been replaced by versions with E-450. SATA ports - fewer;
** Not on sale, but see, for example, ASUS P8H77-I;
*** the author added a network through a homemade raiser, but this is rather personal perfectionism;
**** Prices are estimates at the request of the editors using modern Yandex Market, if not available - Price.ru, if not available - analogues. This is a rough estimate, since some models are no longer on sale and the prices found are not necessarily relevant. The price does not take into account data disks; a used system HDD, if available, was counted as 1000 rubles.
There are subtleties about “quietly”. The first impulse is “complete passive”. However, in most cases the argument is accepted that 4-6 drives will produce more noise than a good 120mm fan at low speed. In any case, you need to understand that you have to pay for everything and a compact case, all other things being equal, will be noisier than a more spacious standard case with large fans.
The obvious feature of a soldered processor is performance. If this is not enough, the vast majority abandon the Mini-ITX format. But, for the sake of completeness, it must be said that this is not necessary, cf. configuration from maestro padavan.
The assembly from Padavan is, as you can see, extremely compact
In December last year, the Intel Atom S1200 (Centerton) for server purposes was announced. When they go on sale, they may be an interesting option for a home NAS. ECC memory support, Intel Virtualization(VT-x), 8 PCI-E lanes, 8 GB of memory - this is enough for most options.
Efficiently extensible
A significant part of NAS builders - some right away, some faced with the limitations of options on Atom-like processors - decide to assemble a configuration that allows for serious expansion. In terms of processor, memory, but above all - in terms of the number of disks. As already mentioned, ready-made NAS even with 4 disks are not cheap, but with 8-10 they are already prohibitively expensive for the home. At the same time, it is not difficult to choose a sufficiently spacious housing. For example, in my case, left over from the upgrade of the Craftway computer (they didn’t save on case hardware back then), there are now 7 units living in it. 3.5″ drives and you can install 3 more without any problems. When choosing a case for a really large number of drives, you should look towards models with many 5.25″ slots, in which you can then install baskets with airflow, using 5.25″ slots for four 3.5″ drives. See the example in the Costs chapter.
Since the NAS operates 24/7, I would like an energy-efficient processor (in Moscow, a watt per year costs 35 rubles). Intel Sandy Bridge and Ivy Bridge seriously reduce power consumption when idle, but the NAS is extremely lightly loaded the lion's share of the time. Therefore, the daily power consumption of such a NAS may be significantly lower than that of the Atom version, which does not know how to reduce consumption when idle. Which processor model to choose depends on whether you need to transcode video in real time.
Many modern TVs have DLNA functionality, which allows you to receive video over a local network. The problem is that they only understand some encoding options. And often they are not at all the ones used by the rips and remixes found on the Internet. The problem can be solved in several ways. (1) Look for movies in a format that matches your TV. It's the tail that wags the dog. (2) Recode the movie on the computer to suit the TV's requests. This is a waste of time and is only possible for a self-made video. (3) Load the NAS with real-time transcoding and (4) Buy a media player, that is, a small box that receives video as files, including via the network with the NAS, and supplies the TV with the receiver with an audio-video signal, usually via HDMI. If you chose option (3), then you need to study the specifications of the TV and look in the Core i7 area. Plus, due to limitations in DLNA in general, and in implementing this marketing idea on your TV in particular, it will not be possible to achieve complete omnivorousness. Option (4) at the current price level turns out to be not only simpler and more functional, but also cheaper. While the NAS processor is suitable for virtually any junior Pentium or Celeron 2nd or 3rd generation Core. You can take the i3, fortunately, compared to the price of the disks, the difference will be negligible. Choose according to your taste. For quick reference or detailed final comparison of candidate models, you can use the processor testing section on iXBT. I took an Intel Pentium G2120 as the youngest Ivy Bridge at that time. Junior Sandy Bridges are cheap and more than sufficient.
The AMD processors available at the time of writing are not impressive compared to Intel - although AMD is much more generous in providing its processors with ECC memory support, and perhaps the company will soon have something competitive, for example the Opteron 3250 with a stated price of $99.
Maternal ASUS board P8H77-M Pro: 7 SATA, up to 32 GB RAM
Motherboard. I took the ASUS P8H77-M Pro for the following reasons:
- LGA1155, we get built-in video automatically due to the processor, it will only be needed at the installation stage;
- maximum number of SATA ports, no matter 3 or 6 Gbit/s (7 SATA + eSATA);
- 4 memory slots are better, but 2 are enough (4, up to 32 GB);
- integrated 1000BaseTX, considered better from Intel. But taking into account the presence of a processor with a reserve of computing power, Realtek will do just fine (Realtek 8111F);
- PCIe slots for future installation of SATA controllers and network cards(x16, x4 in x16 slot, 2 x1);
- Form factor - microATX.
The cooler is selected according to taste, memory - according to the requirements of the selected OS. Here the possible range is from gigabytes to 32.
The power supply is included in a separate chapter.
Examples of the described option:
| by ZanZag | by shale | |
| Frame | Lian Li PC-V354R | InWin BP659 |
| power unit | Chieftec BPS-550C 550 W | 200 W included |
| Motherboard | ASUS P8H67-M EVO(B3) | ECS H61H2-I2 |
| CPU | Intel Pentium G860 | Intel Celeron G530 |
| RAM | 4x4 GB DDR3 PC3-1066 | Kingston 2x2 GB |
| Hard drives for data | 6×Hitachi HDS5C3030ALA630 | 3×Seagate ST3000DM001 |
| System storage | CF 4 GB via CF-IDE adapter | 40 GB SSD |
| operating system | nas4free 9.x | OMV |
| Additionally | cooler Cooler Master DP6-8E5SB-PL-GP, add. fans 2×Zalman FDB-1 and Arctic Cooling F9 PWM | |
| Price estimate | RUB 18,200 | 7300 rub. |
Server-so-server
There is a “premium” category of NAS builders who, for objective or subjective reasons, build NAS from serious and expensive server components. Enthusiasts are experimenting with 10-gigabit network solutions. Remember that server configurations are often not quite compatible with residential premises in terms of size and noise. The ability to use ECC memory is the most obvious advantage of the approach. The ZFS file system used in this segment home NAS-building, actively uses memory. In this case, a memory failure can lead to data corruption that goes unnoticed. ECC memory solves the problem, but its use in the Intel version requires server processors (there are interesting exceptions, for example the Pentium G2120) and motherboards.
Virtualization is often used and several guest OS solve problems, each with their own. A common option is when a SATA controller is forwarded into a virtual machine that performs the storage function (Solaris or FreeBSD with zfs). From this VM, disk capacity is exported via NFS or iSCSI to the hypervisor and other VMs. I will refrain from further explanation of what I myself am not very well versed in and will give real examples.
Assembly from TPAKTOP, outside and inside views
| by fatfree | by axel77 | from TPAKTOP | |
| Frame | Fractal Design Define Mini | Supermicro CSE-SC846E26-R1200B | |
| power unit | Seasonic X560 | ||
| Motherboard | Supermicro X9SCL-F | Supermicro X9SCM-F | Supermicro X9SCM-F |
| CPU | Intel Xeon E3-1230 | Intel Xeon E3-1230 | Intel Xeon E3-1220 |
| RAM | 4×Kingston KVR1333D3E9S/8G | 4×Kingston KVR1333D3E9S/4G | 4×Kingston KVR1333D3E9S/4G |
| Hard drives for data | 5×WD20EFRX | in the process of accumulation | 12xST31000524AS in two 6xRaidZ2 (main pool), 2xST32000542AS in a mirror (backup pool), 4xST3250318AS in a stripe (torrent pool) |
| System storage | Intel SSD 520 180 GB | 2.5″ by 320 GB | TS64GSSD25S-M |
| operating system | ESXi 5.1.0 + Nexenta CE + Ubuntu Server 12.04 + Windows 8 | FreeBSD | FreeBSD |
| Additionally | HBA IBM ServeRAID M1015, Noctua NH-L12 cooler | 2×HBA IBM ServerRAID M1015 | 2×HBA IBM ServeRAID M1015, Intel Gigabit ET Dual Port Server Adapter |
SATA/SAS controllers
So if you can’t wait, you can start. And in the second part we will discuss the software in more detail.
I would like to express my gratitude to all participants in the profile thread on the forum.site, including comrades axel77, half_moon_bay, padavan, ZanZag, shale, whose configurations were used in the article; comrades Sergei V. Sh, TPAKTOP, iZEN and RU_Taurus for many useful comments.
Special thanks to the developers of free software: Olivier Cochard-Labbé, Daisuke Aoyama, Michael Zoon, Volker Theile and many others. They made the very existence of the DIY NAS theme possible.