Most of the arrays listed can be scaled up from a handful of gigabytes to one, two or more terabytes of storage. As such, they would be appropriate for a department that requires 250G to 500G of storage with the ability to expand the system, when necessary, to serve as an enterprise or data center array with even higher storage requirements. The NexStor 8Le and 8FL from nStor operate at a range of RAID levels, with eight drives and single controllers. The extent to which you can scale a particular array depends on how many drives you place in your base module, the individual capacities of those drives and how many extension modules are allowed by the manufacturer. Many of the arrays listed in this guide provide full protection against data loss and high throughput speeds for a per-megabyte cost of 25 cents or less.
RAID works by striping portions of a file across different drives.
A single file may have one segment of data on Drive 1, more data on Drive 2, and so on. Hot-swapping replaces failed drives or controllers without powering down the system, thus saving money and aggravation by eliminating costly downtime. Fault-tolerant RAID components include redundant power supplies, cooling systems, multiple host interfaces, dual buses and dual failover controllers, which direct the secondary controller to kick in immediately if the primary controller fails. Adding fault-tolerant components increases the cost of a RAID system, but they also provide virtually foolproof insurance against cataclysmic system failure and data loss. When researching RAID systems you'll see the term RAID levels.