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Running a db mirroring in sql server 2005 sp2.

There is SAN maintenance that needs to occur and i want to know if I stop SQL Server on the fail-over partner (mirror) and the principal keeps doing log backups, will i need to re-initialize database mirroring (with a full backup) if the mirror is offline for several days?

I have a feeling there is some internal limit I've come across before. I haven't been able to find anything online that references this, and i don't have the time to test this because the SAN people (not be be confused with the sand people) want to do this now!

I am not breaking the mirror and bringing the partner online, so there is no break in the transaction log chain.

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up vote 2 down vote accepted

Do you shouldn't have to restore the full to the other system.

The only reason that you would need to would be if your log on the active system ran out of drive space and you had to remove the mirroring in order to clear the log file.

What sort of SAN maintenance is happening that you have to take the database offline for several days?

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partition resizing. the issue is it's outsourced to a sloppy provider & they can't give us a definite window. So they want us to take the db offline & give them a few days. – Nick Kavadias Aug 24 '09 at 0:00
Yes, I know the transaction log will keep growing on the principal, should be ok for disk space there. – Nick Kavadias Aug 24 '09 at 0:01
Then you should be ok. Disk space is the big stopping point. Other than that Mirroring should just keep running for ever in a disconnected state. – mrdenny Aug 24 '09 at 0:55
Be careful if your log generation on the principle ramps up at busy times. I tend to oversize my logs (pre grow them in 8GB chunks to almost fill the space allocated on our transaction log LUN) for this sort of eventuality (note I only have 1 Prod DB mirrored in this example). – SuperCoolMoss Aug 24 '09 at 10:37

Yup - you shouldn't have a problem.

The reason I've replied is to explain the internal limitation you may have bumped into before - and that's when initially setting up mirroring. When you take the full backup and copy it across to restore on the soon-to-be mirror (plus the mandatory log backup on SQL 2005), if any subsequent log backups have occured on the principal before you enable mirroring, but you didn't copy them over and restore them - mirroring will not start. This is because there's no proof that one of the log backups didn't encompass a period in the BULK_LOGGED recovery model where a minimally logged operation occured. In that case, the log backup is required to ensure the soon-to-be mirror is in-sync with the principal.

Hope this helps

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