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. Performance degradation can occur,
however, 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 those 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 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 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 website
for storage system configuration requirements:
Logical disk configuration guidelines for storage systems
Most storage systems provide some mechanism to create multiple logical disks from a single array. This is useful when the storage system presents storage directly to the hosts.
Optimal storage pool configuration guidelines for storage systems A storage pool provides the pool of storage from which volumes are created. You must ensure that the MDisks that make up each tier of the storage pool have the same performance and reliability characteristics.
FlashCopy mapping guidelines for storage systems
Ensure that you have considered the type of I/O and frequency of update before you create the volumes that you want to use in FlashCopy mappings.