Choosing the Number of State Database Replicas

Before choosing the number of state database replicas, consider the following guidelines.

• A minimum of 3 state database replicas are recommended, up to a maximum of 50 replicas per Solaris Volume Manager disk set. The following guidelines are recommended:

  • For a system with only a single drive: put all three replicas in one slice.

  • For a system with two to four drives: put two replicas on each drive.

  • For a system with five or more drives: put one replica on each drive.

• Additional state database replicas can improve the mirror's performance. Generally, you need to add two replicas for each mirror you add to the system.

• If you have a RAID-1 volume that is to be used for small-sized random I/O (for example, for a database), consider your number of replicas. For best performance, ensure that you have at least two extra replicas per RAID-1 volume on slices (and preferably on disks and controllers) that are unconnected to the RAID-1 volume.