Intel Storage System SSR212PP User Guide 41
PRELIMINARY
Number (1-6 or spare)
You must create at least one disk pool for virtual disks. You can create up to four RAID 5
disk pools or six RAID 1/0 disk pools, numbered 1-6, in a storage system.
If your system has two SPs, you should create at least two disk pools, since the software
assigns one or more disk pools to each SP; that is, it assigns disk pool 1 and all its virtual
disks to SP A, disk pool 2 and all its disks to SP B, disk pool 3 and its disks to SP A, and
disk pool 4 and its disks to SP B. If you create only one pool, all virtual disks in the
storage system will be assigned to SP A.
Disks to Form Each Pool
For each pool, specify the numbers of the disks you will include. The number of disks in a
pool determines its capacity. Generally, we suggest no more than six; the minimum is
three for RAID 5 and two for RAID 1/0 pools.
For maximum use of space on the disks, it is recommended that you do not combine disks
0 through 3 (the operating system disks) in a disk pool with other disks. Part of the space
on the operating system disks is preloaded with system data, and as a result, is not
available for your data. If you combine operating system disks in a disk pool with other
disks, each of the other disks loses space for data equal to the system data space on an
operating system disk.
If you have disks of differing capacities (for example, 250- and 500-Gbyte), always use
disks of the same capacity when creating a disk pool. If the disks have different capacities,
the software will format each disk at the smaller of the two disk sizes, wasting more than
200 Gbytes of potential storage on each larger disk.
When you create disk pools, consider making one disk a hot spare. A hot spare allows
your system to continue running with its normal performance and retain its redundancy if
a disk fails. However, because a hot spare is reserved as a replacement disk, it cannot be
used as a virtual disk. You may not want to devote an entire disk to maintaining
redundancy after a disk failure.
If you create disk pools that use all the storage system disks, no space will remain for a hot
spare. Later, if you need to create a hot spare, you must delete all the virtual disks in the
disk pool, delete the pool, create a new pool, and then create the hot spare and new virtual
disks on the new pool.
Always use a disk with the largest capacity as a hot spare. You can make any disk other
than 0, 1, 2, or 3 a hot spare. If you decide to use a hot spare, write "Spare" in the
appropriate row in column 1 and the disk number in column 2.
If you want to create disk snapshots, that is, capture point-in-time images of a virtual disk,
then you must reserve disk space for snapshot disk resources. The snapshot resource uses
this space transparently for snapshot operations, but the space must be available and not
allocated to any virtual disk. The snapshot resource requires a maximum of 20 percent of
each virtual disk whose point-in-time images you will capture, allocated in 10-Gbyte
blocks. For example, if you will take snapshots of a 290-Gbyte virtual disk, leave 60
Gbytes of disk space unused. Twenty percent of 290 is 58, but space is given in 10-Gbyte
blocks; therefore you must reserve 60 Gbytes.
From Disk 0 through Disk 11, select the disks that you want to include in the disk pool,
and select a disk to be a Hot Spare. Record this information in the Storage System disk
information worksheet.