Performance planning for Metro Mirror

You should understand these performance considerations prior to configuring Metro Mirror.

Before you use Metro Mirror, consider the following requirements and guidelines:

• The source and target volumes in a Metro Mirror relationship must be the same storage type.
• The source and target logical volumes must be the same size or the target must be larger in size.
• For Metro Mirror environments, distribute the work loads by not directing all updates to a small set of common volumes on a single target storage unit. The performance impact at the target site storage unit adversely affects the performance at the source site.
• Similar to any system disk configuration, the number of disk units available to the application can have a significant affect on its performance. Putting additional workload on a limited number of disk units might result in longer disk waits and ultimately longer response times to the application. This is particularly important when it comes to temporary storage in a system configured with independent disk pools. All temporary storage is written to the SYSBAS disk pool. If your application does not use a lot of temporary storage, then you can get by with fewer disk arms in the SYSBAS disk pool. You must also remember that the operating system and basic functions occur in the SYSBAS disk pool.