Under some circumstances, you may wish to change the underlying volume type for ASM disk groups in a cluster running in Azure. This document outlines the process for switching from Standard SSD volumes to Premium SSD volumes. Please contact FlashGrid support for queries on changing to or from any other disk types.
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 (see KB FlashGrid Cluster on Azure. Backup Best Practices) before making this change.
Begin by determining the Logical Unit Number (LUN) of the disk volumes to be changed. This must be for each disk group that is to be changed, for instance, if DATA disk group:
flashgrid-dg show -G DATA
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 (see KB How to Upload Diags for instructions).