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.