Here's a strange one and Im stumped!

[FredB]

I have a server running BE 9.0 backing up Exchange 2000 using the Exchange 2000 Agent from a remote system.  For some reason about two weeks ago the daily incremental backups started giving a corrupt error under the Job Completion Status 'Corrupt data encountered - See job log for details' However when viewing the job log here is the error that is displayed: 

Mailbox _Attachments_

Warning: Unable to backup the attachment data associated with one or more messages. Some messages and their attachments may have been deleted while the backup was already in progress.

This error appears at the end of the backup log for the Exchange 2000 mailboxes.  Needless to say the error description does not explain the problem or what message is corrupt.  The actual error message listed under the Error's Box is as follows:

Backup - \\NAMISHPSEBE02\Microsoft Exchange Mailboxes Warning: Unable to backup the attachment data associated with one or more messages. Some messages and their attachments may have been deleted while the backup was already in progress.

Problem here is nowhere does it say exactly what messages, mailbox or whatever is causing the problem.

Any ideas?

[lyon]

 Under Tools > Options, there is a Job Logs section where one can configure the level of detail for the Job logs. Have you tried turning the level of logging up?

I suspect that you'll find that you have a corrupt attachment that the user may be able to delete to solve this problem.  If not, you'll have to learn how to use the eseutil and isinteg tools to verify your database.

Lyon

[FredB]

 Hi Lyon,
Just an update in case your still interested in this issue.  I did turn up the logging to full detail and it wasnt of much use, it didnt tell me anything more then I was seeing before, unless the full detail does not show up in the normal job log.  I will look into this.

Now the thing is, I have a full backup that runs through the weekend, that backs up the same information on the exchange server as the incremental and it went through fine!  So I opened two consoles and compared the selections and settings between the incremental and full backup job.  The only difference was that the incremental job was configured to utilise single instance backup on the exchange server where the full backup job was not, so i unchecked it from the incremental.  I do not understand why this would have an effect.  I will be able to see how it runs tonight, but I have a sneaking suspision that it will not make a difference which leads me to my next question.  Will the backup have problems running if users leave Outlook open?  Im wondering if I have users leaving outlook open through the night when not shutting down there systems, but most if not all users will close down outlook and shutdown there system for the weekend.

Fred

[lyon]

 
I've had no reason to change the single instance setting.
I work in a 24x7 operation and frequently perform backups with active Outlook users.  Backups do place a load on the server, but it's not usually noticable to users. The only thing that we run into is when users have pst files open - but that only impacts flat file backups on a file server and not Exchange.

Lyon

[THarry · Accepted solution]

Hello, Single Instance is a storage method that Exchange uses to maximise disk space.  If a user in your organization sends an email with a 1 MB attachment to 100 users, that message could end up consuming 100 MB of disk space.  Using single instance storage, Exchange is smart enough to realize that it is not 100 separate attachments, but rather a single attachment 100 times.  So it only stores a single instance of the attachment and thereby saves you 99 MB of storage.

The same setting in BE allows BE to preserve that same space savings, though it can sometimes cause issues when doing incremental backups that could cause the attachment to not be backed up

Harry