State Database Replicas - Introduction

Note: At least 3 replicas are required for a consistent, functional, multi-user Solaris system.

3 - yields at least 2 replicas in the event of a failure
Note: if replicas are on same slice or media and are lost, then Volume Management will fail, causing loss of data.
Note: place replicas on as many distinct controllers/disks as possible

Note: Max of 50 replicas per disk set

Note: Volume Management relies upon Majority Consensu Algorithm (MCA) to determine the consistency of the volume information

3 replicas = 1.5(half) = 1-rounded-down +1 = 2 = MCA(half +1)

Note: try to create an even amount of replicas
4 replicas = 2(half) + 1 = 3

State database replica is approximately 4MB by default - for local storage

Rules regarding storage location of state database replicas:
1. dedicated partition/slice - c0t1d0s3
2. local partition that is to be used in a volume(RAID 0/1/5)
3. UFS logging devices
4. '/', '/usr', 'swap', and other UFS partitions CANNOT be used to store state database replicas