Database mirroring listener port change
Recently we had a client that had to change to all of their IP addresses. This included the DR site which is on another network and not in the same AD. Database mirroring between the two sites broke. Even though mirroring had been setup with FQDN's, internally these were kept as IP addresses in sys.database_mirrroing. Unfortunately you can't update this table - adhoc updates aren't possible (unless you start in single user mode and use DAC). So we had to go through the following process. 1.Stop application activity 2.Remove mirroring (SET PARTNER OFF) 3.Stop Mirroring endpoints (on principal and mirror) 4.Alter Mirroring endpoints to use new IP addresses e.g. ALTER ENDPOINT SET LISTENER_IP = 5.Start endpoints on principal and mirror 6.Enable mirroring (ALTER DATABASE SET PARTNER = TCP://x.x.x.x:yyyy) We then had to make sure the mirroring ports were open on both firewalls for the new IP addresses. Not an easy or quick or pretty process for a relatively minor change.