SQL Server mirroring question

Is it possible to have an Active/Passive cluster in DATACENTER A that will serve as the PRINCIPAL and a single instance database server in DATACENTER B that will serve as the MIRROR?

Reason for this is - in 99,99 % of the case DATACENTER A is the primary site.

Datacenter B will only be used when DATACENTER 1 is completely down.

But to maintain high availibilty in DATACENTER A we setup a cluster instead of A single instance.

==> Principal (= A/P cluster) - Mirror (Single instance) - Would that work?

asked Feb 03 '12 at 02:55 PM in Default

Freddy
36 ● 2 ● 2 ● 4

(comments are locked)

1 answer:

Yes - the active/passive cluster is a single instance and you can mirror the databases in that single instance to another server.

The only thing to consider is that clustering works at an instance-level, whereas database mirroring is at the database level, so you COULD end up with one database being the principle in Datacentre B, with the rest of the databases being in prinicpal role at Datacentre A.

answered Feb 03 '12 at 03:03 PM

Kev Riley ♦♦
46.1k ● 38 ● 43 ● 69

@Kev Riley... Just a short example of the above scenario would be very helpful.

Feb 03 '12 at 03:18 PM Sacred Jewel

Well, there is only one LARGE DATABASE, about 1 TB.

My only concern was/is, if the database is running on node 1 (cluster) and suddenly that node shuts down, the cluster will failover to node 2 as it is an Active/Passive cluster.

As soon as that node 1 shuts down, will the mirror server wait until node 2 takes over and becomes the principal? Or will the mirror become principal as soon as the active node shuts down even though node 2 is still up and should take over and become the principal?

Feb 03 '12 at 03:24 PM Freddy

With Automatic failover configured, the failover to mirror will happen. And after the node 2 is active, the node 2 would remain the miror.

Feb 03 '12 at 03:43 PM Sacred Jewel

Thanks. Is it not possible to configure the witness server to have priorities like:

=> If node 1 is down, wait until node 2 picks up, if node 2 does not pick up withing a reasonable time, failover to the mirror server.

Feb 03 '12 at 03:54 PM Freddy

You may want to forego the Witness and just set up the Mirror for manual failover as you principal HA is the cluster.

Feb 06 '12 at 02:57 PM Blackhawk-17

show 1 more reply

(comments are locked)