Johno02 wrote:
Sounds like a problem with at least one of the drives. With a RAID system, some data may be saved, but best get an expert to try and recover it for you. RAID (redundant array of independent disks) was used to improve performance by spreading data across two or more drives, and to provide a level of redundancy for failures. If you are set up for RAID 1 Mirroring, then all data has a full backup, and you are in good shape. With just two drives, everything may be recovered, but like I said, you probably need help.
raid Mirrowing,
RAID 1 is a "mirrored pair", in a nutshell ALL DATA is written to BOTH DRIVES at the same time..
What you get is "mirror" copies of your data so ALL DATA is "saved" and intact. The Op does not require "help" to recover data and all he needs to do is identify the good drive from the bad one then replace the bad one.
On the next powerup the array will now "rebuild" automatically without any special tools or intervention.. The array manager does this for you..
If the array was set to RAID0 which is "data striping" without "parity" which makes a bigger virtual drive from two or more drives you then get into issues with potential loss of data due to the data being split across one or more drives (written as stripes).. Upside is you gain speed and drive size.. Downside of this is without parity and one of the drives fail you run a lot of risk of losing all data.
RAID5 requires minimum of three drives and uses data striping across the drives plus the added benefit of parity check data. RAID5 is used a lot on servers to increase access speeds plus the added benefit of parity which allows the array to rebuild in the event of a drive failure.
There are lot of other RAID configurations possible depending on the quantity of drives you have and the design of the RAID controller.
