We just migrated our database server from Windows 2012 to Windows 2016, with SQL Server 2014. We have approximately 200 databases running on this server, most of them around 5mb in size.
Almost every morning, I'm getting a report from users saying the databases are inaccessible. When I log in using SQL Management Server, 2-3 of the databases are marked as "Recovery Pending".
If I take them offline, then online again, the database becomes available, with no apparent loss of data.
I've looked through the Windows Event Logs, and I can't see a single error regarding this.
Is there an SQL Server log file somewhere that might shed some light on why this is happening? It seems to happen over night when the office is closed and no-one is using the databases.