You must follow these configuration guidelines and
procedures for your storage system to maximize performance and to avoid potential I/O problems.
General guidelines
You must follow these
general guidelines when you configure your storage systems.
- Avoid splitting arrays into multiple logical disks at the storage system level. Where possible, create a single logical disk from the
entire capacity of the array.
- You can intermix different
block-size drives within an array and a storage pool. However, performance
degradation can occur if you intermix 512 block-size drives and 4096
block-size drives within an array.
- Depending on the redundancy that is required, create RAID-5 (RAID
5) arrays by using 5 - 8 data bits plus parity components (that is,
5 + P, 6 + P, 7 + P or 8 + P).
- Do not mix managed disks (MDisks) that greatly vary in performance
in the same storage pool tier. The overall storage pool performance
in a tier is limited by the slowest MDisk. Because some storage systems
can sustain much higher I/O bandwidths than others, do not mix MDisks
that are provided by low-end storage systems with MDisks that are provided by high-end storage systems in the same tier. You must consider the following factors:
- The underlying RAID type that the storage system is using to implement the MDisk.
- The number of physical disks in the array (for example, 10,0000
or 15,0000 RPM) and the physical disk type (for example, Fibre Channel
or SATA).
- When possible, include similarly sized MDisks in a storage pool
tier to make it easier to balance the MDisks in the storage pool tier.
If the MDisks in a storage pool tier are significantly different sizes,
you can balance the proportion of space that is allocated on each
MDisk by including the larger MDisk multiple times in the MDisk list.
This configuration is specified when you create a new volume. For
example, if you have two 400 MB disks and one 800 MB disk that are
identified as MDisk 0, 1, and 2, you can create the striped volume
with the MDisk IDs of 0:1:2:2. This configuration doubles the number
of extents on the 800 MB drive, which accommodates it being double
the size of the other MDisks.
- Complete the appropriate calculations to ensure that your storage systems are configured correctly.
- If any storage system that is associated with an MDisk has the allowquorum parameter set to no, the chquorum command fails for that MDisk. Before
you set the allowquorum parameter to yes on any storage system, check the following Web
sites for storage system configuration requirements: