RAID and Subsystem Architectures
RAID Configurations
Comparing RAID 0+1 and 1+0
RAID 0 + 1
Block C1
Block C2
Block C1 Block C2
Block B3
Block B4
Block B3
X
Block B4
Block B1
Block B2 =
Block B1 Block B2
Block A5
Block A6
Block A5 Block A6
Block A3
Block A4
Block A3 Block A4
Block A1
Block A2
Block A1 Block A2
Reverts to an unprotected RAID 0 if there is a single disk failure in any
stripe. Cannot recover from a failure in both stripes
Block C1 Block C1 Block C2 Block C2
RAID 1 + 0 Block B3
=
X
Block B3 Block B4
=
X
Block B4
Block B1
==
Block B1 Block B2 Block B2
Block A5 Block A5 Block A6 Block A6
Block A3 Block A3 Block A4 Block A4
Block A1 Block A1 Block A2 Block A2
Can recover from a disk failure in either stripe. If there is a disk failure
in both stripes on the same mirror, then data is lost.
RAID 0 + 1 (Striped mirroring array):
If we lose a disk in one of the stripes, then all the data is lost in that
stripe and the volume reverts back to an unprotected RAID 0
If we lose a second disk anywhere in the other stripe then all data is lost.
RAID 1 + 0 (Mirrored striping array):
If we lose a disk in one of the stripes, then the data can be recovered
from the mirrored disk.
If another disk fails, then data can still be recovered from the mirror.
If both disks in the same mirror fail, then all data is lost.