Seeding a cluster using the GAB auto-seed parameter through I/O fencing

If some of the nodes are not up and running in a cluster, then GAB port does not come up to avoid any risks of preexisting split-brain. In such cases, you can manually seed GAB using the command gabconfig - x to bring the GAB port up.

See Manual seeding of a cluster.

However, if you have enabled I/O fencing in the cluster, then I/O fencing can handle any preexisting split-brain in the cluster. You can configure I/O fencing in such a way for GAB to automatically seed the cluster. The behavior is as follows:

This feature is disabled by default. You must configure the autoseed_gab_timeout parameter in the /etc/vxfenmode file to enable the automatic seeding feature of GAB.

See About I/O fencing configuration files.

To enable GAB auto-seeding parameter of I/O fencing

To disable GAB auto-seeding parameter of I/O fencing