Any housing, casing or dedicated storage system that contains more than one hard drive working in unison with all the other drives with the purpose of storing and sharing data is almost certainly going to be a RAID storage device.
Most home users and smaller businesses will have some sort of NAS (Network Attached Storage) device with one or more hard drives. Unfortunately, most of the low-end units use a configuration of RAID 0. However, RAID 0 is an oxymoron; RAID stands for “Redundant Array of Independent Disks” – with “redundant” meaning that even if a single drive fails, the data will still be accessible. Not so with this one. A failed RAID 0 array (even with a single drive failure) will prevent all access to the data and the services of a RAID data recovery company will be required. These low-end NAS systems almost invariably have little or no active cooling, and should be avoided where possible.
Higher up the scale are larger, more professional NAS systems capable of supporting various RAID levels such as RAID 1, RAID 5 and RAID 6. These systems often have active cooling, although the fact that some of these have warning lights for overheating drives (rather than fan failure warning lights) leads us to believe they are not adequately cooled. Professional units will have the facility for a hot-spare drive. Quite simply, it means that if one of the active drives in the array develops a fault or even fails completely, it will “pick up” the hot spare and automatically rebuild the array. During the RAID rebuild, the array runs in a degraded state, which has a marked impact on performance.
At the top end of the NAS scale are advanced systems with multiple, simultaneous RAID levels, including multiple redundant power supplies, fans, RAID controllers and multiple hot-swap drives. Some of these devices have the ability to take “snapshots” of data, adding yet another layer of redundancy in the event of failure.
At the top of RAID Storage Devices are SANs (Storage Area Networks) by StorNext (and Apple’s XSan, derived from StorNext) and storage farms. These are massive, high speed, high capacity storage arrays generally situated in dedicated, climate-controlled rooms.
