When a DB Master of the secondary site fails, you can restore it from backup or a snapshot. If this does not work, perform the following steps to promote a DB server from the same site to a new DB Master.
WARNING:It is recommended to prepare a snapshot of the DB server before conversion to ensure that you have a backup if the conversion fails. Conversion is a risky operation and can be performed only if you do not have the snapshots of the broken server to restore.
Ensure that the DB Master is turned off as a pre-requisite.
Open the Advanced Authentication Administration portal on the GMS.
Click Edit for any DB server which must be converted to DB Master in the same site.
Wait until the conversion is complete.
Open the Advanced Authentication Administration portal of the DB server (DB server that is converted to DB Master in step 3).
Wait till the conversion is complete.
Reboot all the servers.