sql 2016 alwayson question about failover

Question

Hi guys, i have this question. we have 2 sql 2016 standard with some databases replicated with basic alwayson. So last night the primary server crashed (BSOD and reboot) and the secondary sql has started the failover. This morning i have done a manual failover to move again the DB on primary server. i have a doubt, the manual failover need to be done from the sql with primary replica? or from the sql with secondary replica? or doesn't matter? thanks Andrea

Answer 1

You can initiate a manual failover from either the Primary or Secondary. I prefer the Primary in order to see the AG dashboard show correct information.

Answer 2

hi, thanks for reply

from your experience after the failback (with option "replica with no data loss") is useful run a checkdb for this database?

cheers

Andrea

Answer 3

Hi @geradmin ,

> i have a doubt, the manual failover need to be done from the sql with primary replica?

You can do manual failover on primary replica or secondary replica. Before manual failover, please make sure the primary replica and the target secondary replica are running in synchronous-commit mode and are currently synchronized.

> after the failback (with option "replica with no data loss") is useful run a checkdb for this database

As Shashank mentioned, suggest you do not do that. DBCC CHECKDB is an IO intensive operation, this operation will have some performance implications. After failover, suggest you using AG dashboard to check the AG state.

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Answer 4

Hi, yes when i did the failback on wizard's windows the state of replica was green. To be sure I ran the integrity check anyway, the DB the wa have is small, the biggest is 50GB and the checkdb has took 10 minutes.

thanks

Andrea