It's true that certain configurations of RAID servers can be exceptionally reliable, due to their built-in redundancy, auto rebuild functions, and fault tolerance. One benefit of a RAID server in a RAID 5 configuration is that if a hard drive fails, the RAID controller can rebuild the data volume from a hot standby drive.
What's a Hot Standby?
If you're not familiar with RAID server terminology, a hot standby, sometimes called a hot spare, is a redundant hard drive built into your RAID configuration. Normally, it serves no function and sits in “standby mode.” (Hence the name.) But when another drive in your RAID array fails, the hot standby can step in to save the day. (It's kind of like 24 Hour Data in that regard!)
That is, unless your RAID array doesn't have a hot standby.
Performing a Hot Swap
If your RAID server wasn't configured with a hot spare, you can still perform a hot swap. Ideally, a hot swap takes place while the server is still running, with no interruption in its operation.
You just remove one hard disk drive from the RAID array and replace it with a drive of the same size, make and model. The ability to perform hot swaps is another feature that gives RAID arrays their reputation for reliability.
When RAID Servers Fail
However, if you don't have a hot standby and you don't have a duplicate hard drive available to perform a hot swap, you could be looking at trouble: the catastrophic loss of data and a need for emergency data recovery services for your RAID array.
In the time between hard drive failure and the delivery of your replacement drive for a hot swap, the raid array runs in a degraded mode, putting added stress on the remaining drives. When two hard drives fail in a RAID array, this can create cascading, system-wide failure.
Additionally, since most hard drives in a RAID array are about the same age and have been through the same number of read and write cycles, when one fails, others may not be far behind. While you're waiting for your replacement drive, one or more additional drives may fail.
That's when you need emergency data recovery services for your RAID array. And that's exactly when 24 Hour Data is standing by, to help you recover your mission critical lost data and rebuild your RAID array.