Under some circumstances, you may wish to change the underlying volume type for ASM disk groups in a cluster running in Azure. For instance, where a cluster has been deployed with Standard SSD volumes, but you require improved performance by changing to Premium SSD volumes.
This process requires careful planning and carries a risk of data loss - we recommend you discuss this process with Flashgrid Support before proceeding, and strongly suggest taking a backup of all database data and configuration files before making this change.
Begin by determining the lun numbers of the disk volumes to be changed using flashgrid-dg
show -G <diskgroup>
The example below shows the configuration for the DATA ASM disk group on a two RAC-node cluster. To change volumes associated with the DATA disk group, the following luns must be modified:
- database server rac1 - lun 2, 3, 4
- database server rac2 - lun 2, 3, 4
- quorum server racq - lun 3
[fg@rac1 ~]$ flashgrid-cluster
FlashGrid 22.3.10.30914 #8ddf36c2698cd715e733fa9573a61c3ddf1c0152
[..]
Cluster status: Good
------------------------------------------------------------
Node Status ASM_Node Storage_Node Quorum_Node Failgroup
------------------------------------------------------------
rac1 Good Yes Yes No RAC1
rac2 Good Yes Yes No RAC2
racq Good No No Yes RACQ
------------------------------------------------------------
--------------------------------------------------------------------------------------------------------
GroupName Status Mounted Type TotalMiB FreeMiB OfflineDisks LostDisks Resync ReadLocal Vote
--------------------------------------------------------------------------------------------------------
DATA Good AllNodes NORMAL 6291456 6290984 0 0 No Enabled None
FRA Good AllNodes NORMAL 3145728 3145256 0 0 No Enabled None
GRID Good AllNodes NORMAL 10240 9424 0 0 No Enabled 3/3
--------------------------------------------------------------------------------------------------------
[fg@rac1 ~]$ flashgrid-dg show -G DATA
FlashGrid 22.3.10.30914 #8ddf36c2698cd715e733fa9573a61c3ddf1c0152
[...]
-----------------------------------------------------------------------------
FailGroup ASM_Disk_Name Drive Phys_GiB ASM_GiB Status
-----------------------------------------------------------------------------
RAC1 RAC1$LUN2 /dev/flashgrid/rac1.lun2 1024 1024 ONLINE
RAC1 RAC1$LUN3 /dev/flashgrid/rac1.lun3 1024 1024 ONLINE
RAC1 RAC1$LUN4 /dev/flashgrid/rac1.lun4 1024 1024 ONLINE
RAC2 RAC2$LUN2 /dev/flashgrid/rac2.lun2 1024 1024 ONLINE
RAC2 RAC2$LUN3 /dev/flashgrid/rac2.lun3 1024 1024 ONLINE
RAC2 RAC2$LUN4 /dev/flashgrid/rac2.lun4 1024 1024 ONLINE
RACQ RACQ$LUN3 /dev/flashgrid/racq.lun3 1 1 ONLINE
-----------------------------------------------------------------------------
Change the volume type for the required luns on each virtual machine, beginning with the first database server (rac1):
-
Make sure there are no other nodes that are in offline or re-syncing state. All disk groups must have zero offline disks and Resync = No:
# flashgrid-cluster -
If the node is a database node,
a. Stop all local database instances running on the node.
b. Stop Oracle CRS on the node:
# crsctl stop crs -
Power off the node using flashgrid-node command. It will gracefully put the corresponding failure group offline.
# flashgrid-node poweroff - Stop the node VM using Azure console.
- Confirm database(s) remain accessible through remaining servers, and check cluster status with
flashgrid-clustercommand on remaining server(s). - Change the disk volumes (lun 2, 3 & 4 in this example for the database server) for the DATA ASM disk group to Premium SSD LRS type by following the steps described in this Azure article.
- Start the server - this could take longer than usual, as the server will need to be re-deployed on new hardware within Azure (due to being de-allocated earlier).
- Check cluster status is Good, and ensure all disk groups have zero offline disks
# flashgrid-cluster - Wait until cluster status shows Resync = No for all disk groups. Resync must complete before proceeding to the next server.
- Repeat steps 1-9 above for database server rac2, and then the quorum server racq
Once all changes are made, upload the cluster diagnostics to FlashGrid Support for a final review.