Configuration guidelines for storage systems

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 traditional 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 drives 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 website for storage system configuration requirements: