The Importance of Validating Backups

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The Importance of Validating Backups

Paul Randal

One Orange Chip

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September 23, 2012 at 5:57 pm

#393240

Comments posted to this topic are about the item The Importance of Validating Backups
Paul Randal
CEO, SQLskills.com: Check out SQLskills online training!
Blog:www.SQLskills.com/blogs/paul Twitter: @PaulRandal
SQL MVP, Microsoft RD, Contributing Editor of TechNet Magazine
Author of DBCC CHECKDB/repair (and other Storage Engine) code of SQL Server 2005

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Divine Flame SSCoach Points: 15943 More actions · Answer 1

Thanks Paul for writing such a nice article & clarifying the importance of "WITH CHECKSUM" option when taking the backups! 🙂

Sujeet Singh

M&M SSC-Insane Points: 21700 More actions · Answer 2

M&M

SSC-Insane

Points: 21700

September 24, 2012 at 3:21 am

#1541305

Great stuff as usual by the SQL legend 🙂

M&M

Paul Brewer SSCrazy Points: 2955 More actions · Answer 3

Paul Brewer

SSCrazy

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September 24, 2012 at 3:32 am

#1541307

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Gazareth One Orange Chip Points: 27737 More actions · Answer 4

Paul Brewer (9/24/2012)
cannot cope with databases with more than 1 data file at the moment.

Hi Paul,

Been working on a similar script myself - I use RESTORE FILELISTONLY to get the data files & also to generate the MOVE statements.

Happy to send you over some code, although it'll probably need modifying to fit your process.

My starting point is the backup files themselves, rather than msdb database.

Cheers

Gaz

Grant Fritchey SSC Guru Points: 398872 More actions · Answer 5

Well you know I loved this article. I've been ranting about this issue for quite some time. It's nice to have yet another resource to point to in order to try to get the point across. Thanks Paul.

"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt

Author of:
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Gazareth One Orange Chip Points: 27737 More actions · Answer 6

Yes, thanks for the article Paul.

Is there actually an easy way to check the output from DBCC CHECKDB?

I currently scan the SQL log using xp_readerrorlog for the DBCC output info, another way is to use TABLERESULTS clause, and check for the completion line.

However, both methods could be called undocumented - you won't find either in BOL!

Charlie Wongy SSC Rookie Points: 37 More actions · Answer 7

Great article.

Is it possible to use DBCC CHECKDB to check the database first before backing up (with all your other recommendations), so that we don't have to restore the backup to perform that test?

chrisfradenburg SSCrazy Eights Points: 9592 More actions · Answer 8

I recently talked my boss into getting a drive big enough to restore all of our DBs so we can pull them from tape and do tests on a few each week. Now just comes the job of automating that which is likely to be very fun. It would also appear that we need to do some work to secure our backups a little better.

charles.wong (9/24/2012)
Great article.
Is it possible to use DBCC CHECKDB to check the database first before backing up (with all your other recommendations), so that we don't have to restore the backup to perform that test?

You can run CHECKDB first but there's no guarantee that the DB doesn't get corrupt before the backup is done. It also won't guarantee that the backup file itself doesn't get corrupted. Some people recommend doing an integrity check and if the DB is corrupt not to back it up (assuming that this means you may be deleting the last good backup.) Our process here is to backup the database since we send the backups to another location so we shouldn't be destroying a good backup. It also means that we have a copy of the corrupt DB so if we need to restore we can then do some comparisons to try and recover some of the changes. The thing you need to be careful of is making sure you're not destroying the last good backup because then you have a problem.

Paul Randal One Orange Chip Points: 29544 More actions · Answer 9

Glad you all like the article!

Some of the questions:

1) If you can run CHECKDB on the prod system, go for it. But also do the backup/copy/restore/CHECKDB process too. Defense in depth - just like with security.

2) Did CHECKDB complete and find errors? Check the value of @@ERROR afterwards - guarantees to be non-zero if CHECKDB found/had a problem.

Cheers

Paul Randal
CEO, SQLskills.com: Check out SQLskills online training!
Blog:www.SQLskills.com/blogs/paul Twitter: @PaulRandal
SQL MVP, Microsoft RD, Contributing Editor of TechNet Magazine
Author of DBCC CHECKDB/repair (and other Storage Engine) code of SQL Server 2005

Michael Meierruth SSChampion Points: 10051 More actions · Answer 10

Paul,

I have a few automated backups running in various places.

They typically are started via a .bat file launching sqlcmd.exe with the -i parameter pointing to the .sql file issuing the backup command.

The occassional restore I had to do never presented a problem. But I prefere to be on the safe side.

Once I have put the WITH CHECKSUM into the .sql file, how is an error signaled?

What sort of message is generated? If so, I suppose it's in the sqlcmd.exe output which I would have to pipe into a log.

Does sqlcmd.exe return a DOS error code of some sort in this case?

Thanks.

DBA_Learner SSCarpal Tunnel Points: 4228 More actions · Answer 11

Restore verify only with checksum can only be used when the backup file which queried with checksum. If we do not do backup file with checksum, we cannot use the command Restore verify only with checksum

Paul Brewer SSCrazy Points: 2955 More actions · Answer 12

Paul Brewer

SSCrazy

Points: 2955

September 24, 2012 at 8:51 am

#1541454

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JamesMorrison Hall of Fame Points: 3213 More actions · Answer 13

JamesMorrison

Hall of Fame

Points: 3213

September 24, 2012 at 9:49 am

#1541481

deleted

Zivio! Ten Centuries Points: 1032 More actions · Answer 14

Thanks for the great article, Paul. I was one of those "people around the world asking for help with corrupt databases, where their recent backups also contained the corruption" whom you mercifully helped years ago!

QUESTION: The database maintenance plan dialogs in Microsoft SQLServer2000 (yes, we're still running it) has a "Verify the integrity of the backup upon completion" option. Is this the same as the "WITH CHECKSUM" option?