APPENDIX
106
RAID 1
RAID 1 is also known as “disk mirroring”; data written on one
disk drive is simultaneously written to another disk drive. Read
performance will be enhanced if the array controller can, in paral-
lel, access both members of a mirrored pair. During writes, there
will be a minor performance penalty when compared to writing
to a single disk. If one drive fails, all data (and software applica-
tions) are preserved on the other drive. RAID 1 offers extremely
high data reliability, but at the cost of doubling the required data
storage capacity.
