The majority of Network Attach Storage (NAS) and Storage Area Network (SAN) units contain multiple hard disks using in a RAID array configuration. Most of these are attached to the network in order to present storage space for use by other networked computers and devices.
These storage devices were typically used only in the enterprise level market for large companies and data centres. During the last decade, the price of hard drives, including NAS ready disks has dropped dramatically making NAS units to be affordable across all market sectors, including media servers used in the home. These units should be configured correctly with their health monitored regularly, to avoid the requirement for data recovery.
Network Attached Storage Units
Once a NAS has been configured it should operate faultlessly as a file storage area with little or no maintenance. These provide storage for use by any computer attached to the network using any operating system, including Windows, OSX, Linux, BSD etc. A NAS unit may be a simple system, allowing any user on the network to access the storage space, or at the high end may be a multiuser system with individual storage quotas per user, which cater for all sectors of the market.
Many NAS systems, particularly those sold as personal cloud storage, include the ability to automatically copy files to a cloud server as backup. NAS units simplified the act of storing data centrally, without the need to set up complex data shares on a server or desktop system, which may require rebooting on a more regular basis. NAS systems are required to be always available as a file server.
Storage Area Network Units
SAN systems are still mainly used in the enterprise market, almost exclusively in data centres. A SAN unit presents disk space to specified computer system using a network protocol, as though it is connected directly to the system in the same way as an internal hard disk drive. This is particularly important for adding disk space to rack mounted server efficiently, without the need for physical reconfiguration, which would be both time consuming and inefficient. This is particularly important for systems which require the maximum amount of uptime.
To provide the fastest possible data transfer speed, most SAN units are connected using 10Gbe network cards. It is common for a SAN system to contain data from multiple server system, without the need to understand the file system being stored on the disks. Such systems are using maintained carefully, often using failover servers and data backups. This means that data recovery from such systems is fairly rare.
RAID Configuration and Data Recovery
The RAID configuration used in a NAS or SAN system is extremely important, as it not only determines the data transfer speed, but also the level of redundancy. A RAID 0 striped configuration may be tempting, due to the increased data transfer speed, combine with storage space efficiency, but the lack of redundancy would put your data at risk unless a robust data backup is used. It is now more common to use RAID 1 or RAID 5 configurations, sometimes in combination with RAID 0, to increase the data transfer speed, while maintaining redundancy.
The RAID data recovery specialists at DiskEng have extensive knowledge and experience of recovering data from both NAS and SAN systems, instrumental in their high level of success. Most NAS and SAN failures are usually the result of multiple catastrophic hard disk failures or due to an ill-fated attempt at DIY data recovery, the latter often resulting unnecessary loss of data.