HP Surestore Disk Array FC60 HP SureStore E Disk Array FC60 Service Manual (A5 - Page 50

Raid 0/1

Page 50 highlights

Figure 19 shows the distribution of data on a RAID 1 volume group. Note that all data on the data disk is replicated on the disk mirror. Figure 19 RAID 1 Volume Group RAID 0/1 RAID 0/1 uses mirroring to achieve data redundancy and disk striping to enhance performance. It combines the speed advantage of block striping with the redundancy advantage of mirroring. Because all data is mirrored, a RAID 0/1 volume group has a storage efficiency of 50%. A RAID 0/1 volume group contains an even number of from four to 30 disks. One half of the disks are primary disks and the other half are disk mirrors. The disks in a RAID 0/1 volume group are mirrored by the disk array hardware, which automatically writes data to both disks in the mirrored pair. For highest data availability, each disk in the mirrored pair must be located in a different enclosure. When a disk fails, the disk array automatically uses the remaining disk of the mirrored pair for data access. A RAID 0/1 volume group can survive the failure of multiple disks, as long as one disk in each mirrored pair remains accessible. Until the failed disk is replaced (or a rebuild on a global hot spare is completed), the volume group operates in degraded mode. While in degraded mode, the volume group is susceptible to the failure of the second disk 50 Disk Array High Availability Features

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50
Disk Array High Availability Features
Figure 19
shows the distribution of data on a RAID 1 volume group. Note that all data on
the data disk is replicated on the disk mirror.
Figure 19
RAID 1
Volume Group
RAID 0/1
RAID 0/1 uses mirroring to achieve data redundancy and disk striping to enhance
performance. It combines the speed advantage of block striping with the redundancy
advantage of mirroring. Because all data is mirrored, a RAID 0/1 volume group has a
storage efficiency of 50%.
A RAID 0/1 volume group contains an even number of from four to 30 disks. One half of the
disks are primary disks and the other half are disk mirrors. The disks in a RAID 0/1 volume
group are mirrored by the disk array hardware, which automatically writes data to both
disks in the mirrored pair. For highest data availability, each disk in the mirrored pair must
be located in a different enclosure.
When a disk fails, the disk array automatically uses the remaining disk of the mirrored pair
for data access. A RAID 0/1 volume group can survive the failure of multiple disks, as long
as one disk in each mirrored pair remains accessible. Until the failed disk is replaced (or a
rebuild on a global hot spare is completed), the volume group operates in degraded mode.
While in degraded mode, the volume group is susceptible to the failure of the second disk