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Backup Exec 12 - Exchange 2007 - Consistency Check

bwlonsdale
Level 2
Partner
I've recently noticed that there is an option selected under our Exchange backup that has me a little worried.

It's "Continue with backup if consistency check fails" - I always understood one of the key indicators that there was a problem with an Exchange database is when your backup failed because of inconsistency/corruption. Why would you allow a backup to continue? Should this option only be selected when you know for a fact you've already got corruption and you need a backup? Although why still escapes me, I would have thought that you'd be performing a restore in this case, not backing it up.

What happens to the log files if you let an inconsistent backup complete - are they truncated as normal? What happens during a restore if you try and recover an inconsistent exchange database? Will it mount?
5 REPLIES 5

RahulG
Level 6
Employee

As per the query you have , you understand the option ncorrect . the consistency check it peforms is for the vss provider not the exchange database . so the backup would be fine and you can also restore the database if it was able to backup the databse without the consistency check for the vss.

RahulG
Level 6
Employee
Additionally you can follow the this documents
http://support.veritas.com/docs/285294
and follow this steps
1. Check the VSS writer status on the exchange by running the command vssadmin list writers

2. Run the Microsoft Exchange Information Store backup in a separate job without Advanced Open File Option (AOFO) enabled

bwlonsdale
Level 2
Partner
Would you please point me to some articles detailing this option?

From the help file:

Select this option if you want the backup job to continue even if the consistency check fails. You may want the job to continue if you think a backup of the database in its current state is better than no backup at all, or if you are backing up a very large database that may have only a small problem.

...which to me says the database is inconsistent or corrupt, not the VSS Snapshot.

I can understand if you're in a dire need of a backup because of space issues with the logs or if it's a very large database and you are moving users out to a new database because small errors don't force the database to dismount, but even still - it seems like that is an option which would normally stay unticked and only be ticked when absolutely necessary.

Sorry, I need to be sure about what's happening when that box is ticked and what situations I will be in if it does find errors and backs up the data anyway.

The link in the second reply:

http://seer.entsupport.symantec.com/docs/285294.htm

These are already separate jobs with AOFO disabled.

RahulG
Level 6
Employee
Select this option if you want a consistency check to
be performed when the option Microsoft Volume
Shadow Copy Service is selected. The option Microsoft
Volume Shadow Copy Service is automatically used
whenever a software backup is selected on the
Advanced Disk-based Backup Option backup properties.
You can also select the Microsoft Volume Shadow Copy
Service on the Advanced Open File Option backup
property page.
The consistency check, which is run on the snapshot,
determines if possible data corruption exists.
If this option is selected, and the dependent option
Continue with backup if consistency check fails is not
selected, then data for specific Exchange objects that
are determined to be corrupt are not backed up. All
other non-corrupt Exchange objects are backed up.
For example, if any transaction log file for a Storage
Group is corrupt, then none of the transaction log files
are backed up for that Storage Group when the
Continue with backup if consistency check fails option
is not selected. However, the Exchange database files
are backed up if Backup Exec determines they are not
corrupt. Similarly, if a specific Exchange database file
is corrupt, then backup is skipped only for that corrupt
database file. All other non-corrupt database files and
transaction log files are backed up.
When the option Continue with backup if consistency
check fails is enabled, then all Exchange data is backed
up regardless if corrupt files exist....

From admin Guide

RahulG
Level 6
Employee
 its recommended to check this option to continue if the consistency check fails so it would backup the data which you have so you have some data instead of no data ...