Setting up RAID
37
Drawbacks
Unfortunately, RAID 0 lets multiple drives
behave as one in another way. If part of the array
fails (such as a hard drive crashing), the entire
array fails. Because the drives are treated like a
single drive, parts of files (including operating
system files) can be spread across several drives,
leaving the computer with only file fragments if
one drive fails. Regular and frequent backups are
critical.
Another drawback is that RAID 0 treats each hard
drive as if it has the storage capacity of the
smallest drive in the array. So if you have three
drives (300 GB, 250 GB, and 200 GB) in a RAID 0
array, your computer only recognizes 600 GB
total capacity.
RAID for security
RAID 1 maintains a complete copy of a file set on
each physical hard drive in the array. Maintaining
simultaneous, complete copies of files across
multiple hard drives is called
mirroring
. If a drive
fails, the mirrored drive takes over and acts as the
primary drive.
File reading performance (
seek time
) is increased
using the same methods that RAID 0 uses,
although writing speed is the same as if writing
to a single hard drive.
A
B
C
A
B
C
RAID 1
8511781.book Page 37 Tuesday, October 10, 2006 4:41 PM
