Multiplex Voting Files on Oracle RAC 12c

Voting Files are stored on ASM disk from 11GR2. Place where Clusterware stores Voting files called voting disk. Oracle Clusterware Software creates multiple Votingfiles during installation  to avoid voting disk failures. If we Install Oracle Clusterware software with External redundancy we will get 1 OCR and VOTING FILES on Diskgroup; If we check, Normal Redundancy during Installation, Oracle Clusterware Software require 3 disks for a diskgroup. Oracle Clusterware software creates Original Copy and Mirror copy of OCR inside diskgroup and 3 Voting files on diskgroup i.e 1 voting file per each disk in a diskgroup. If we Check High redundancy during installation 3 copy's of OCRS | 5 Voting Files on 5 disks inside the diskgroup;

Clusterware maintain Voting disk to know heartbeat of the nodes in a cluster. 
When ever node joins a cluster, voting file updated. When ever voting file is updated, Clusterware software starts communicating with node.i.e CRS demon on one node will communicate with CRS demon on another node. Then On each node, clusterware software starts its services and resources.  

Technically CSSD monitor will update Voting files on each disk inside the diskgroup. For every second CSSD process updates (Node availability information) to the voting files. Atleast each node has to  access  2/3 voting files. If any node is unable to access 2/3 of voting files, it evicts from cluster. OPROCD kills the node in a cluster to protect data integrity. From 11GR2, OCR will backup the votingfiles. If votingfiles are corrupted, we can recover using backup taken by OCR. 

We know that Votingfiles are stored on ASM, we can find Out using Following Query 

[root@tnc1 ~]# crsctl query css votedisk

##  STATE    File Universal Id                File Name Disk group

--  -----    -----------------                --------- ---------

 1. ONLINE   4bbee2aa15204fb5bf311cc8ebcedd10 (/dev/sdh2) [NEVOT]

Located 1 voting disk(s).

Currently we have only 1 Voting file on the cluster. If this Voting file is corrupted, All nodes in a cluster will evict from the cluster. 

To Stabilize RAC Environment, Multiplex Voting Files in Oracle RAC. 

To Multiplex Voting files, Create a new diskgroup using "ASMCA or SYSAM" with NORMAL Redundancy or High redundancy and Replace Voting files from old diskgroup to New diskgroup; 

OLDDISKGROUP: NEVOT 

NEWDISKGROUP: GRID

Make sure, New disk group is mounted on all instances 

SQL> select name,group_number,state from v$asm_diskgroup;

---

Replace  Voting files from One OLD ASM diskgroup (External Redundancy) to another NEW ASM diskgroup (High Redundancy). perform operation as root user from any node of the cluster 

Successfully, Voting files are  Replaced / Multiplexed on Oracle RAC Cluster

--Nikhil Tatineni--

--12c Oracle RAC--