Symptoms
Consider the following scenario:
-
You have a database availability group (DAG) that contains multiple database copies, including one lagged database copy.
-
You have a MetaCacheDatabase (MCDB) configured in Exchange Server 2019.
-
The Exchange server hosts the MCDB and the active mailbox copy.
-
The SSD that the MCDB is running on fails.
In this scenario, a failover of the mailbox database is triggered, and you expect that the second preference mailbox database copy will be mounted. However, the lagged database copy is replayed and mounted instead.
Resolution
To fix this issue, install the following cumulative update:
Cumulative Update 14 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019
