liteswitch (8/15/2012)
Now, I want the cluster to operate in a synchronous mode, with a witness
Let's clear the confusion first, you mean mirror session not cluster
liteswitch (8/15/2012)
if the cluster is failing over between nodes (planned or unplanned), I do not want the witness to fail over the mirroring session to the mirrored instance (as the databases will be offling briefly during cluster failover). I am only going to make the databases fail over to the mirror if the SAN fails and is going to be offline for a considerable time and I need databases online and serving clients.
yes this is something to think about, you'd be surprised how many people don't and then can't work out why their mirror session goes bonkers when the cluster goes offline.
One thing you will need to do is a test on your cluster to see exactly how long failover takes, take this calue in seconds and add a bit and then increase the miror session timeout from the default 10 secs 😉
liteswitch (8/15/2012)
Now, in the database mirroring configuration via SSMS (not T-SQL), if I select "High safety without automatic failover (synchronous), the text box detailing the witness server blanks out.
That is by design, if you dont want automatic failover in high safety then you don't have a requirement for a witness
liteswitch (8/15/2012)
If I choose to manually fail over the mirroring to the mirror instance. My method of rollback will be a manual backup of the database from the mirror, restoring it to the cluster, and then manually failing over the mirroring back to using the cluster as the principal.
In high safety synchronous without witness you dont need to take the manual backup. When the first manual failover occurs you will be failing over from clustered principal to the mirror which will then become live. Once the cluster is back up and online and the databases are synchronised you simply perform a manual failover back to the original clustered primary.
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