• If you lose 1/2 or more of all of your voting disks, then nodes get evicted from the cluster, or nodes kick themselves out of the cluster. It doesn’t threaten database corruption. Alternatively you can use external redundancy which means you are providing redundancy at the storage level using RAID.
  • For this reason when using Oracle for the redundancy of your voting disks, Oracle recommends that customers use 3 or more voting disks in Oracle RAC 10g Release 2.
  • Note: For best availability, the 3 voting files should be physically separate disks. It is recommended to use an odd number as 4 disks will not be any more highly available than 3 disks, 1/2 of 3 is 1.5rounded to 2, 1/2 of 4 is 2, once we lose 2 disks, our cluster will fail with both 4 voting disks or 3 voting disks. 
  • Restoring corrupted voting disks is easy since there isn’t any significant persistent data stored in the voting disk. See the Oracle Clusterware Admin and Deployment Guide for information on backup and restore of voting disks.