June 14, 2010 at 8:57 am
I want to setup DB mirroring with automatic failover. I don't want to purchase another server for the sole purpose of a witness server so I was wondering what the issues if any would be if any by installing the witness on my web server. I plan on having my web and db server in an offsite location. Thanks.
June 22, 2010 at 8:44 pm
There shouldn't be any issues with this, I have not heard of SQL Express having issues with IIS. I would recommend setting up WSRM to ensure available Resources for SQL, cause IIS can be a bit of a hog.
June 23, 2010 at 5:47 am
Thanks for the reply.
I didn't know you can use SQL Express as Mirror Witness.
Do you know if you need a valid license to run a witness if you use SQL Standard?
I know the mirror server doesn't need a license unless it becomes a production server so I assumed you don't need one for the witness either.
June 23, 2010 at 8:43 pm
Not sure about the licencing of Standard edition if it is just a witness. Based on knowledge of other licencing states, as long as there are no users connected to user databases then licencing is not required for the server, this is the case for mirroring and log shipping, so this could apply to standard hosting witness,I suppose. But easier to deploy express because you will have no user databases there anyway.
July 8, 2010 at 7:55 am
i would be concerned with running the witness remotely. (unless you mean the principal and mirror will be remote also :-P)
the witness may initiate false fail overs because of latency issues.
of course, if your app is coded very well, then fail overs won't matter.
July 8, 2010 at 8:00 am
Geoff,
The witness would be local to the primary but the mirrored server would be located at a remote facility.
July 8, 2010 at 8:13 am
AVB,
the witness really should go with the mirror. I know there is no best practice to justify this, but in my testing, it is easier to recover in a datacenter disaster if you loose a combo of witness and mirror vs. witness and principal.
the reason is because if you lose datacenter 1 (where the principal is) everything will failover to the mirror.
if you lose datacenter 2 (where the mirror and witness are) you will only have to remove mirroring to get the principal to start up.
in your proposal, IF you lose datacenter 1 (where the principal and witness are) you will have to (on the mirror server) run ;
ALTER DATABASE <database_name> SET PARTNER FORCE_SERVICE_ALLOW_DATA_LOSS
that means you might be forced to roll back vs roll forward.
just my 2 cents.
July 8, 2010 at 8:18 am
Geoff,
Thanks for the info. I can place the witness anywhere. I'm still in the planning stages so I haven't tested or rolled anything out yet!
Viewing 8 posts - 1 through 7 (of 7 total)
You must be logged in to reply to this topic. Login to reply