User's Manual

l "Organizing Data Storage for Availability and Performance"
l "Comparing RAID Level and Concatenation Performance"
l "Controller-supported RAID Levels"
l "Number of Physical Disks per Virtual Disk"
l "Maximum Number of Virtual Disks per Controller"
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RAID Level 1 (Mirroring)
RAID 1 is the simplest form of maintaining redundant data. In RAID 1, data is mirrored or duplicated on one or more physical disks. If a physical disk on one
side of the mirror fails, then the data can be rebuilt using the physical disk on the other side of the mirror.
Figure 3-3. Mirroring Disks
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RAID 1 Characteristics:
l Groups n + n disks as one virtual disk with the capacity of n disks. The controllers currently supported by Storage Management allow the selection of
two disks when creating a RAID 1. Because these disks are mirrored, the total storage capacity is equal to one disk.
l Data is replicated on the two disks.
l When a disk fails, the virtual disk still works. The data will be read from the failed disk's mirror.
l Better read performance, but slightly slower write performance.
l Redundancy for protection of data.
l RAID 1 is more expensive in terms of disk space since twice the number of disks are used than required to store the data without redundancy.
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Related Information:
See the following:
l "Organizing Data Storage for Availability and Performance"
l "Comparing RAID Level and Concatenation Performance"
l "Controller-supported RAID Levels"
l "Number of Physical Disks per Virtual Disk"
l "Maximum Number of Virtual Disks per Controller"

RAID Level 5 (Striping with distributed parity)
RAID 5 provides data redundancy by using data striping in combination with parity information. Rather than dedicating a physical disk to parity, however, the
parity information is striped across all physical disks in the disk group.
Figure 3-4. Striping Disks with Distributed Parity