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Exchange 2003 backup slow using Netbackup 7.0

Created: 11 Aug 2010 • Updated: 13 Sep 2010 | 3 comments
MohdAlim's picture
This issue has been solved. See solution.

Hi

I am using Netbcakup 7.0 to backup Exchange 2003 mailboxes. The backup is extremely slow, getting about 1MB/s or lesser. Is this normal? Any ways to improve the backup speed?

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Oddy's picture

MohdAlim,

Yes, this is normal. Mailbox backups is connecting through an exchange mapi session and has to read all the individual messages in the mailboxes, so it is painfully slow. I would guess 1 mb/s is about what you can expect.
 
You can split up the mailboxes in several streams which will increase the overall performance.
i.e if you want to split the mailbox backup in 4 streadm put in the Backup Selection list

NEW_STREAM
Microsoft Exchange Mailboxes:\[a-f]*
NEW_STREAM
Microsoft Exchange Mailboxes:\[g-l]*
NEW_STREAM
Microsoft Exchange Mailboxes:\[m-r]*
NEW_STREAM
Microsoft Exchange Mailboxes:\[s-z]*

And tick the Allow multiple datastreams in the Policy Attributes for the mailbox policy.
You also need to set the Max job per client to at least 4 under the Host Properties for the Master server under the Global Attributes tab.

If this is still not quick enough for you I would recommend to look into Granular Exchange backups.

I hope this helps.

/Oddy

SOLUTION
Marianne's picture

That is normal for mailbox backups due to the process involved. Do you really HAVE to backup mailboxes? Read up on Recovery Storage Group to restore an Information Store from where individual items can be restored.

See this TechNote:
http://seer.entsupport.symantec.com/docs/280826.htm

If file system backups from the Exchange client are running at a satisfactory speed, then most likely there is no performance tuning within NetBackup which will improve the speed of mailbox backups.  There are two general ways to perform baseline testing of Exchange Mailbox backup throughput for the purpose of determining the theoretical maximum possible throughput for mailbox backups:

1. The exmerge utility from Microsoft is used to extract the data directly out of the database into a .pst file.  The utility should be used to export a few larger mailboxes, and the performance on these mailboxes can be used to gauge the time it should take to complete the backup process.  The utility does create a log file which can be viewed after the process has run to gauge the amount of time the process took. Since this is a Microsoft utility, refer to this Microsoft link for operating instructions:  

 http://support.microsoft.com/?kbid=174197

............
Note: Several factors can impact mailbox backup performance:  
- The creation of more message items in the database creates more data to back up, along with more fragmentation in the database, decreasing access time.  
- Running an antivirus scanner in On-Access/VAPI mode causes a scan of every item backed up and significantly degrades the process.  
- Database defragmentation running at the same time as the mailbox backup degrades the performance.
- Very large mailboxes with many message items have increased initial scan times and slow backup performance.

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links

MohdAlim's picture

Thanks everyone for the advise. Marianne, mayb I will look towards the RSG approach. But it seems Backup Exec 2010 has a better throughput for Exchange compared to Netbackup. They can complete backing up a 250GB mailbox in 7-8 hours time using their current Backup Exec 2010. With Netbackup 7.0, it's not possible to achieve that.

Not sure if the idea of replacing Backup Exec 2010 with Netbackup 7 is really such a good move...