HP Surestore Disk Array FC60 HP SureStore E Disk Array FC60 - (English) Advanc - Page 53

Raid 3,

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Product Description 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 LUN 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 LUN operates in degraded mode. While in degraded mode, the LUN is susceptible to the failure of the second disk of the pair. If both disks fail or become inaccessible simultaneously, the data on the LUN becomes inaccessible. Figure 20 illustrates the distribution of data in a four-module RAID 0/1 LUN. The disk block addresses in the stripe proceed sequentially from the first pair of mirrored disks (disks 1 and 2) to the second pair of mirrored disks (disks 3 and 4), then again from the first mirrored disks, and so on. Figure 20 RAID 0/1 LUN RAID 3 RAID 3 uses parity to achieve data redundancy and disk striping to enhance performance. Data is distributed across all but one of the disks in the RAID 3 LUN. The remaining disk is used to store parity information for each data stripe. A RAID 3 LUN consists of three or Disk Array High Availability Features 53

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Disk Array High Availability Features
53
Product Description
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 LUN 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 LUN operates in degraded mode. While in degraded
mode, the LUN is susceptible to the failure of the second disk of the pair. If both disks fail
or become inaccessible simultaneously, the data on the LUN becomes inaccessible.
Figure 20
illustrates the distribution of data in a four-module RAID 0/1 LUN. The disk block
addresses in the stripe proceed sequentially from the first pair of mirrored disks (disks 1
and 2) to the second pair of mirrored disks (disks 3 and 4), then again from the first
mirrored disks, and so on.
Figure 20
RAID 0/1
LUN
RAID 3
RAID 3 uses parity to achieve data redundancy and disk striping to enhance performance.
Data is distributed across all but one of the disks in the RAID 3 LUN. The remaining disk is
used to store parity information for each data stripe. A RAID 3 LUN consists of three or