Log file truncation on AG database

Question

I am POCing AlwaysON DAG for my company, and i have come into a very interesting debacle. Seems like even though primary and replica's and all synced up, the log file on the primary DB does not get truncated automatically even with a checkpoint. It would have to wait for a log backup to be issued. Does it mean that even with AG, we still need to have scheduled TLOG backups running?

Answer 1

Always ON is nothing but a special type of mirroring. You will have to schedule log backups the same way you do for any sql server database with full recovery model. You do have option to offload backups to secondary node (very helpful). Copy_only full backups and normal log backups are the only possible ones on secondaries though. However, Differential backups are not possible on secondaries.

Please go through this articale, it explains in depth how this owrks and what all possibilities you have :

Backup strategy for AG

Answer 2

Since the databases in an AG always have to have Full Recovery Model, yes, the databases definitely need log backups scheduled frequently to avoid excessive log file growth.