Zeroing out bad block?

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Zeroing out bad block?

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Gail Shaw SSC Guru Points: 1004504 More actions · Answer 1

If you stop SQL Server, can you copy the files? Alternately, did that snapshot backup work, can you restore that elsewhere and check that it's OK?

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
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Mick Opalak SSCommitted Points: 1631 More actions · Answer 2

All of our testing has been on a snapshot backup. We're not trying anything in production.

David Benoit SSC-Dedicated Points: 34562 More actions · Answer 3

Have you run the DBCC against the production database then? Just trying to make sure that I understand the last post correctly.

David

@SQLTentmaker

“He is no fool who gives what he cannot keep to gain that which he cannot lose” - Jim Elliot

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 4

So the bad block came across with the snapshot backup? Ow... Try copying the files with SQL stopped, see if that will get rid of it,

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

Mick Opalak SSCommitted Points: 1631 More actions · Answer 5

We can try that, but we'll have to find a window to bring down production.

Ben Thul SSChasing Mays Points: 638 More actions · Answer 6

Dumb question, but have you engaged either or both of Netapp or Microsoft?

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 7

Mick Opalak (6/4/2012)
We can try that, but we'll have to find a window to bring down production.

For what? CheckDB is an online operation. Will add lots of load to the DB, but doesn't require that the DB is inaccessible.

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

Steve Jones - SSC Editor SSC Guru Points: 736212 More actions · Answer 8

You can keep trying to do this without impacting production, but you run the risk, perhaps a serious risk, of losing lots of your data. You need to spend the resources, and potentially downtime, to fix this.

As Gail said, kick this off in production. You need to know what you have there.

I'd also start restoring older backups elsewhere and running DBCC to make sure you have a clean backup to get back to if something happens. This could die anytime, and then you'd be seriously down.

Mick Opalak SSCommitted Points: 1631 More actions · Answer 9

We did run CHECKDB on production and it did come back clean. On the Snap copy we made CHECKDSK was run and it found the bad block and marked as so. Now the SQL backup finishes successfully on the copy. So that's good news, but the boss still wants to find a way to correct the bad block and not just mark it bad and ignore it. We have Netapp involved.

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 10

And checkDB completes successfully on the copy once the block has been marked bad?

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

Mick Opalak SSCommitted Points: 1631 More actions · Answer 11

So it turns out that the solution is going to be clearing out the bad block at the storage level via a Netapp tool. We've tested the process on a Snapshot copy of the database and it works without corrupting the database.

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 12

CheckDB comes back clean after doing so?

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass

Mick Opalak SSCommitted Points: 1631 More actions · Answer 13

GilaMonster (6/8/2012)
CheckDB comes back clean after doing so?

Yep.

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 14

Then I would say take at least one more snap backup and proceed with caution (and frequent CheckDBs)

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
We stand on the bridge and no one may pass