Exchange 2007 DB - slow backups/offline defrag using eseutil

[lafleur1977]

Hello,

 

I have been struggling with slow backups of our servers using Backup Exec for quite a while. I have been looking into it and found that our main Exchange DB was one of the resources taking ages (about 20 hours - full or diff!). I don't have alot of knowledge with Exchange and the server was configured for us so we manage it day to day really. Looking into how to improve exchange DB backup times I came across a suggestion to perform an offline defrag using eseutil (http://technet.microsoft.com/en-us/library/aa998249(v=exchg.80).aspx) which almost certainly has never been done before. I have also checked the online maintenance schedule of the database which runs from midnight to 4am but the main database keeps terminating due to interruption (probably from the backup job). My question is how safe is performing an offline defrag with eseutil and is this sensible to run considering my backup problem and also how often should it be run?

 

Thanks

[Max_Power]

The defrag will remove the white space allocation from within the database, thus shrinking the database. which should improve the backup time because its not bothering about the actual white space.

 

How big if your database - generally its hard to say how long you would be without mail for which is the main concern (or was for us at least), found a document once where Microsoft said it would take typically 4-7GBs per hour in an offline defrag.

 

If you are prepared to be without mail for that period of time,and you have a complete backup of the server before defragging the Database I would say the risk is minimised (you have a backup so if it goes pear shaped restore it).

 

How much white space do you have within your database? Before defragging it make sense to ask users to perform some house keeping (delete unwanted rubbish, archive etc), then remove the recoverable items via a power shell command and then finally de frag.

[psydii]

Is BEWS under a maintenance agreement? If so give Symantec a call...

 

Silly question: You have tried rebooting the servers to see if that helps?

[lafleur1977]

The defrag will remove the white space allocation from within the database, thus shrinking the database. which should improve the backup time because its not bothering about the actual white space.

 

How big if your database - generally its hard to say how long you would be without mail for which is the main concern (or was for us at least), found a document once where Microsoft said it would take typically 4-7GBs per hour in an offline defrag.

 

If you are prepared to be without mail for that period of time,and you have a complete backup of the server before defragging the Database I would say the risk is minimised (you have a backup so if it goes pear shaped restore it).

 

How much white space do you have within your database? Before defragging it make sense to ask users to perform some house keeping (delete unwanted rubbish, archive etc), then remove the recoverable items via a power shell command and then finally de frag.

 

Thanks for your reply Max_Power. Our DB is about 80 GB currently so I guess it will take about 15 hours or so. We have scheduled for email to be down one day next week over closure and I will make a backup too. Not sure how much white space there is. Is there a way of checking? I would love to ask users to do some housekeeping, but it won't happen unfortunately. Teachers!

[lafleur1977]

Is BEWS under a maintenance agreement? If so give Symantec a call...

 

Silly question: You have tried rebooting the servers to see if that helps?

 

Unfortunately not, which is fun troubleshooting all th various problems BE likes to through up Might look into getting one if possible, if I can't get anywhere with improving the backup times. Yes, have tried rebooting.

 

Thanks

[lafleur1977]

Not sure how much white space there is. Is there a way of checking?

 

Ahh sorry ignore me. I've checked in event logs and the DB in question says it has 27 MB free after online defrag. However this may not be accurate as it gets interrupted... what do you think? Still worth doing an offline defrag?

[Max_Power]

Thanks for your reply Max_Power. Our DB is about 80 GB currently so I guess it will take about 15 hours or so. We have scheduled for email to be down one day next week over closure and I will make a backup too. Not sure how much white space there is. Is there a way of checking? I would love to ask users to do some housekeeping, but it won't happen unfortunately. Teachers!

 

if you use this powershell command itll tell you the amount of space actually used and the amount of white space - both together will add up to your database size.

 

Get-MailboxDatabase -Status | Sort-Object DatabaseSize -Descending | Format-Table Name, DatabaseSize, AvailableNewMailboxSpace

[psydii]

I'd suggest you make a line for 'backup system - annual costs' in your budget, and include the maintenance agreement for your tape drive/disk array and software used, as well as any new tapes / disks required.

[Max_Power]

20 hours for a backup of an 80GB exchange database seems excessive - I would think there is something else not quite right.

 

Is that backing up to a Tape? what kind of rate you getting during backup? have you got the individual mailboxes to backup or you backing up as one complete database?

[lafleur1977]

20 hours for a backup of an 80GB exchange database seems excessive - I would think there is something else not quite right.

 

Is that backing up to a Tape? what kind of rate you getting during backup? have you got the individual mailboxes to backup or you backing up as one complete database?

 

Nope backup to disc. I posted another post about the setup. Our data is also taking about 20 hours so two elements to troubleshoot http://www.edugeek.net/forums/enterprise-software/112174-backupexec-12-5-full-backups-50-hours.html#post959383

 

Backup rate for the exchange storage group, which includes the 80 GB staff DB and another unused DB, is 61 MB/min. Not great at all...

[psydii]

"HP Disk Array configured by a Windows software RAID (as it wouldn't work in a hardware RAID)"

 

That would be the first place I'd look. If you've got an HP disk array that wont let you create a RAID Volume/group you've got a fundamental problem. However may not be the root cause for your backup problems...

 

Are these 2008 R2 boxes? If so perhaps taking a performance trace using the System Performance Data Collector Set template, on both the exchange server and the backup server, might give us some hard data to work with?

Edited May 23, 2013 by psydii

[sukh]

I wouldn't do an offline defrag, I would create a new DB and moves across to it. This reduces the downtime for your users as the move are performed "online" so no outage. This is preferred than a offline defrag.

 

You will have a new DB to backup. Post the results.

[bart21]

I would do as Sukh says and create a new database to move the mailboxes into as this will eliminate the white space. One thing to bear in mind though mailbox moves in exchange 2007 are offline moves. This means that the users will not be able to access the mailboxes whilst they are being moved. I believe others have said they are online, this would be correct for 2010 but not 2007.

 

Nick

[sukh]

correct you can't dk online moves with 2007 only. I assumed you were us 2007.

[DMcCoy]

Before you mess with anything else, have you actually done any throughput testing of the equipment yet?