Table of Contents:
- Direct Attached Storage (DAS)
- Network Attached Storage (NAS)
- Storage Area Network (SAN)
- What To Choose – DAS, NAS, or SAN?
The strategy of any business is to reduce risks and increase profits. One way to achieve this goal is to develop the right policies for corporate information management and retention.
Information is the driving force behind modern business and is considered the most valuable strategic asset of any enterprise. The volume of information is growing exponentially along with the growth of global networks and the development of e-commerce.
Success in business requires an effective strategy for storing, protecting, sharing, and managing data. The most important elements of the information network are servers, data storage systems (DSS), and technologies for their administration.
Today, there is one traditional storage architecture – Direct Attached Storage (DAS) – and two relatively new ones – Network Attached Storage (NAS) and Storage Area Network (SAN). Let’s take a closer look at them and find out what is the best choice for your business, DAS or SAN / NAS solutions.
Direct Attached Storage (DAS)
DAS technology implies a direct (direct) connection of drives to a server or to a PC. In this case, drives (hard drives, tape drives) can be both internal and external. The simplest case of a DAS system is a single drive inside a server or PC. In addition, the organization of an internal RAID array of disks using a RAID controller can also be attributed to a DAS system.
A DAS system is usually understood as an external rack or basket with disks, which can be considered a standalone storage system. In addition to an independent power supply, stand-alone DAS systems have a specialized controller (processor) for managing an array of drives. For example, a RAID controller with the ability to organize RAID arrays of various levels can act as such a controller.
It should be noted that stand-alone DAS systems can have several external I/O channels, which makes it possible to connect several computers to the DAS system at the same time.
The 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 stand-alone storage systems.
The main advantages of DAS systems include their low cost, ease of deployment and administration, and high speed of data exchange between the storage system and the server. Actually, it is for this reason that they have become very popular in the segment of small offices and small corporate networks.
At the same time, DAS systems also have their drawbacks – first of all, this is the high cost of storing and managing data due to their dispersion throughout the organization, as well as the forced network downtime when new disks are added and the need to increase the memory or processor power of the server when a certain size is exceeded. disk space.
Congestion of network traffic with the addition of new servers complicates the problem of data protection, hinders the efficient use of resources, etc. Costs and new problems are snowballing.
Network Attached Storage (NAS)
NAS systems are network-attached storage systems that are directly connected to the network in the same way as a networked print server, router, or any other network device. In fact, NAS systems are an evolution of file servers.
This approach to organizing data storage systems is currently the most popular in the segment of small local networks but 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.
In addition to an optimized OS, freed from all functions that are not related to the maintenance of the file system and the implementation of data input/output, NAS systems have an access-optimized file system. NAS systems are designed in such a way that all of their computing power is focused solely on file serving and storage operations.
The operating system itself is located in flash memory and is preinstalled by the manufacturer. Connecting NAS devices to the network and configuring them is a fairly simple task and within the power of any experienced user, not to mention the system administrator.
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.
Storage Area Network (SAN)
SAN is a specialized storage network infrastructure (SAN). These networks are integrated as separate specialized subnets into a local area (LAN) or wide area (WAN) network.
Essentially, SANs link one or more servers (SAN servers) to one or more storage devices. SANs allow any SAN server to access any storage device without loading other servers or the local network. In addition, it is possible to exchange data between storage devices without the participation of servers.
SANs allow a very large number of users to store information in one place (with fast centralized access) and share it. RAID arrays, various libraries (tape, magneto-optical, etc.), as well as JBOD systems (disk arrays not combined in RAID) can be used as data storage devices.
To build SANs, either the Fiber Channel (FC) standard or the iSCSI standard is used.
What To Choose – DAS, NAS, or SAN?
Until now, DAS is still dominating the world. This situation is likely to continue in the market segments of home computers, small businesses, and large machines (mainframes). The niche of medium and large enterprises will gradually be occupied by SAN and NAS systems and in combined use.
It is expedient to use SAN systems where data access is carried out at the level of physical blocks. We are talking primarily about distributed databases built on a client-server architecture. These are enterprise management systems, banking, and financial systems, where the number of transactions per unit of time is critical, digital television broadcasting, etc.
In addition, SAN systems are used to ensure the uninterrupted and uninterrupted operation of critical applications, the failure of which can lead to the loss of critical data, equipment failure, or other consequences that entail costly downtime of the information system.
NAS systems are used in cases where data is accessed at the file level, these are business applications with simultaneous access of users of different platforms to the same files (multimedia, graphics, documents), consolidation of disparate enterprise information in one place, storage of archives, fast, inexpensive and license-free increase in disk space on the network.