We attempted to re-add the other server as a DAG Member after the customer removed it with the following command:
Add-MailboxDatabaseCopy -Identity "MAILBOXDATABASE" -MailboxServer "EXHANGESERVER"
The DB was created, however the seed fails. This can be caused by real-time anti-virus on Exchange servers without the appropriate exclusions in place or a corrupt transaction log / or inconsistent transaction log checkpoint file.
To fix this we forced the seed using the following procedure:
- We dismounted the active database.
- We suspended the passive copy (if active)
- We deleted the EDB and Log Files from the Passive Server. (You can move these to a different location as an alternative).
- We checked the Active Server was in a clean shutdown state - see https://clintboessen.blogspot.com/2010/09/flush-transaction-logs-in-exchange.html
- Once we know the Active Server database was in a clean shutdown, we cleared all transaction logs only from the production server by moving the logs to a temp folder.
- We then re-mounted the Active Server database. This database needed a force mount (Mount-Database DatabaseName -Force)
- Lastly we forcefully updated the passive server with the following command: