Question : SQL Server Mirroring Witness

For disaster recovery purposes, I intend to implement off site SQL Mirroring. I understand the concepts of a witness server and the primary/mirror servers, but when reading the documentation about automatic failover, I'm left with a question.

The primary server is running in our main office. It serves a single database which is used by an in house application.

The secondary server, as well as the witness, will run in an off-site data center. The two sites will be connected by VPN. The amount of data change is relatively small and performance won't be an issue, so I intend to run in high safety mode.

If my primary server goes offline, users can RDP into the application server which runs off-site and is set to connect to the mirror server. I know that the witness will take care of failing it over automatically when it loses contact with the primary server.

However, if the off-site mirror and witness lose connection for any reason, will the primary server fail over and stop serving the database because it's lost quorum? If so, my local users will be kicked offline just because the connection has been terminated, even though the primary server is still available.

If this is the case, would log shipping (I know that it requires manual failover and involves data loss) be a more effective option for me?

Thanks for your input.

Answer : SQL Server Mirroring Witness

In high availability mode, if you lose quorum then the primary server becomes unavailable. You can manually restore it, of course, but I sense you want something more automatic.

To maximize availability you should isolate the witness from both the primary and the server such that you are unlikely to lose any two at the same time.

You are better off with a manual fail-over mode than with log shipping. It's easier to administer, fail over is easier, and the secondary will be more up-to-date.  With the advent of mirroring, I would only use log-shipping for situations where you want multiple recovery sites.  Even then, I'd probably use it in conjuction with mirroring or replication.