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Voting Disk Setup in a 12c Grid Infrastructure Extended RAC Environment

by admin on 25th October 2013 No comments

I was asked to configure a new 12c Grid Infrastructure environment for a customer recently. As part of this the Oracle Grid Infrastructure Management Repository (the CHM Repository) would be configured so the size of the ASM disk group would need to be much bigger than previously and I also wanted to find out how the Quorum based NFS voting disk would work in this new situation.

In summary, not much has changed apart from the size and the Quorum disk remains just that.

I started off with a Normal Redundancy ASM Disk Group (OCRVOTE) with 3 x 10 GB LUNs presented (OCRVOTE1, OCRVOTE2 and OCRVOTE3).

[root@ ~]# crsctl query css votedisk
## STATE File Universal Id File Name Disk group
-- ----- ----------------- --------- ---------
1. ONLINE 898a1b4a12e14fd0bfac44781420a9e2 (ORCL:OCRVOTE1) [OCRVOTE]
2. ONLINE ba5a0ec486d54f7cbfe4274d359fd7fb (ORCL:OCRVOTE2) [OCRVOTE]
3. ONLINE 7356bfa7d7844ffabf16d1c5e1d70200 (ORCL:OCRVOTE3) [OCRVOTE]
Located 3 voting disk(s).

I created a 500 MB ‘disk’ on my NFS mount point:
$ dd if=/dev/zero of=/voting_disk/vote_quorum bs=1M count=500

I then launch the ASM Configuration Assistant (ASMCA):
1

Right click on OCRVOTE and select ‘Add Disks’. I had to change my Disk Discovery Path to be ‘ORCL:*,/voting_disk/*’ for the NFS disk to show up.

3

I select the disk and tick the Quorum Box and press OK.4

A check shows that the 3 voting disks are still in the same place so we need to remove the temporary 3rd Voting File and replace it with the NFS based disk.

[root@ voting_disk]# crsctl query css votedisk
## STATE File Universal Id File Name Disk group
-- ----- ----------------- --------- ---------
1. ONLINE 898a1b4a12e14fd0bfac44781420a9e2 (ORCL:OCRVOTE1) [OCRVOTE]
2. ONLINE ba5a0ec486d54f7cbfe4274d359fd7fb (ORCL:OCRVOTE2) [OCRVOTE]
3. ONLINE 7a1a99a6743d4f2abf1a061ee764bdb9 (ORCL:OCRVOTE3) [OCRVOTE]
Located 3 voting disk(s).

Back into ASMCA and this time, right click on the OCRVOTE disk group and select ‘Drop Disks’

5

Select the ORCL:OCRVOTE3 disk and click OK.

6

If we take a quick look at the new configuration in ASMCMD we can see a rebalance is currently in place.
ASMCMD> lsdg
State Type Rebal Sector Block AU Total_MB Free_MB Req_mir_free_MB Usable_file_MB Offline_disks Voting_files Name
MOUNTED NORMAL Y 512 4096 1048576 20972 13501 10236 1400 0 Y OCRVOTE/

[root@ voting_disk]# crsctl query css votedisk
## STATE File Universal Id File Name Disk group
-- ----- ----------------- --------- ---------
1. ONLINE 898a1b4a12e14fd0bfac44781420a9e2 (ORCL:OCRVOTE1) [OCRVOTE]
2. ONLINE ba5a0ec486d54f7cbfe4274d359fd7fb (ORCL:OCRVOTE2) [OCRVOTE]
3. ONLINE efd0792521db4fedbf04ff59886fad17 (/voting_disk/vote_quorum) [OCRVOTE]
Located 3 voting disk(s).

We have relocated our 3rd voting disk to our 3rd site on NFS.

The main thing here is that the voting disks need to be at least 10GB for an extended cluster layout with a 3rd quorum NFS disk.

adminVoting Disk Setup in a 12c Grid Infrastructure Extended RAC Environment

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