NAS and SAN RAID Arrays

The vast majority of Network Attach Storage (NAS) and Storage Area Network (SAN) enclosures contain multiple hard disk drives configured as a RAID array. NAS and SAN device are usually attached to the local area network, presenting the storage space to be used by other networked devices.

With the price of hard drives falling and the demand for more storage space, SAN and NAS units are now not only used by enterprise customers, such as large companies and data centres, but also by small and medium businesses. Media servers for use in the home are also NAS devices and becoming increasingly common, meaning the demand for data recovery is also rising. Should your SAN or NAS device fail, it should be sent for professional data recovery.

Network Attached Storage (NAS)

A NAS box is expected to operate as a standalone unit providing a centralised file storage area, which once set up requires little maintenance. Most NAS devices are attached to the network and capable of being accessed by most current operating systems, such as Linux, Windows, OS X etc. The simplest NAS storage devices allows any computer to access the files through a single user login, while the most complex aimed at the enterprise market provide multiuser access which can have storage quotas allocated for each user.

Many of the latest NAS boxes also provide protocols which allow them to attach to a cloud service provider and back the data up. A NAS system should be continuously available as a file server for all computers on the network, which can also be used to share files between users, removing the need to setup shares on individual computers, which could pose a security risk.

Storage Area Network (SAN)

SAN systems are almost exclusively used for enterprise level data storage solutions, particularly within data centres. The storage space on a SAN is usually split into discrete sections, which are then presented as though it were a hard disk drive attached directly to a specific computer on the network. This allows extra storage to be added to a system without the need to physically install a hard drive inside the system. This is of particular use when rack mounted servers are used enabling storage to be added without the need for any downtime.

As most SAN systems are used within data centre, they are usually attached to a 10Gbe network which is able to provide faster data transfer speeds than the usual 1Gbit network connection used by most computer systems in the office and at home. It is common for a SAN system to contain data from multiple servers, without the need to have any knowledge of the underlying file systems. Such systems are usually subject to high levels of maintenance, in many cases utilising fail-over servers and backup strategies, which means data recovery due to a failure is rare.

NAS and SAN Data Recovery

When you initially configure your NAS system it is important to configure it with the most appropriate RAID level, typically one which utilises fault tolerance through redundancy. RAID 0 striped arrays are very tempting due to the fast speeds and efficiency of storage space usage, but the risk of a failure occurring is increased as even a single drive failure will cause the array to go offline. The most secure is RAID 1 mirroring providing full data redundancy, while RAID 5 gives a good compromise between fault tolerance, disk usage and transfer speeds.

DiskEng have gained a wealth of experience recovering data from NAS systems and a smaller number of SAN units, usually resulting in a high level of success. Data loss is usually the result of multiple catastrophic disk failures, operator errors or an ill-fated attempt to recover the data, which should be left to a professional data recovery company, such as DiskEng.

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