Greetings,

So we have 2 Exchange 2013 servers running on a Server 2012 R2 platform. They are member servers of a single DAG, and 1 witness server. My question is, how safe is it to restart the witness server alone to apply updates? Better yet, is there a process or sequence in which to restart the witness and member servers after applying Windows updates?

Any help/suggestions will be very appreciated.

Thank you!

With an even number of nodes and if the network connection between the sites / DAG members is furthermore online, the DAG remains online, too.

If the network connection is broken, too, the DAG will shutdown the DBs.

Hi Jon.Knight,

Thank you very much for your response. So are you saying it is not advisable to restart the witness server on its' own to apply updates?

Thanks.

no its fine the dag will not failover when you shutdown the witness if you have an even number (2)

BUT if you lose network between the two dag nodes whilst the witness if down the databases will shutdown. 

So should be ok if its a reboot

• Marked as answer by Carlucci01 13 hours 41 minutes ago

There is no issue if you give updates to witness server and restart the machine. if you shutdown witness server and database preference ( "member Server") server 1 simultaneously, it will affect DAG because there is no witness server for transferring roles to second server.

Update witness server at first

then first member server

then second member server

Regards,

Joby

• Marked as answer by Carlucci01 13 hours 41 minutes ago

Excellent - Thank you very much guys, I appreciate the resourceful input.

no its fine the dag will not failover when you shutdown the witness if you have an even number (2)

BUT if you lose network between the two dag nodes whilst the witness if down the databases will shutdown. 

So should be ok if its a reboot

• Marked as answer by Carlucci01 Friday, June 26, 2015 5:44 PM

There is no issue if you give updates to witness server and restart the machine. if you shutdown witness server and database preference ( "member Server") server 1 simultaneously, it will affect DAG because there is no witness server for transferring roles to second server.

Update witness server at first

then first member server

then second member server

Regards,

Joby

• Marked as answer by Carlucci01 Friday, June 26, 2015 5:44 PM