These are some of the things to look out for with MetroCluster and can be considered best practices and recommendations.
Disable change_fsid
One very important configuration change to be done on MetroCluster controllers is to immediately disable the change_fsid option. If it is not disabled the all volumes and LUNs will be renamed during failover and make it impossible to volumes and LUNs to be referenced. This is really critical for LUNs.
To avoid the FSID change in the case of a site takeover, you can set the change_fsid option to off (the default is on). Setting this option to off has the following results if a site takeover is initiated by the cf forcetakeover -d command:
- Data ONTAP refrains from changing the FSIDs of volumes and aggregates.
- Users can continue to access their volumes after site takeover without remounting.
- LUNs remain online.
If you don’t disable the change_fsid option in MetroCluster configurations the following happens when the cf forcetakeover -d command is run:
- Data ONTAP changes the file system IDs (FSIDs) of volumes and aggregates because ownership changes.
- Because of the FSID change, clients must remount their volumes if a takeover occurs.
- If using Logical Units (LUNs), the LUNs must also be brought back online after the takeover.
options cf.takeover.change_fsid off
MetroCluster RC file
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