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exchange 2007 backup is slow

Level 3
we are having netbackup 6.5.3 with exchange is in cluster mode (active/active/passive0

The mailbox  Backup of one exchange server is very slow. but the information store runs fast

One exchange server is taking 9 hours for backing up data and another one is taking more than 1 day.

Are there any known resolutions???



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DOCUMENTATION: How to back up Exchange mailboxes to a null device to baseline throughput for Exchange Mailbox Backups

Veritas NetBackup (tm) 4.5 for Microsoft Exchange Server System Administrator's Guide on Windows NT/2000
Veritas NetBackup (tm) 5.0 for Microsoft Exchange Server System Administrator's Guide for Windows
Veritas NetBackup (tm) 5.1 for Microsoft Exchange Server System Administrator's Guide for Windows
Veritas NetBackup (tm) 6.0 for Microsoft Exchange Server System Administrator's Guide for Windows

Modification Type: Supplement

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:

2. The second option is a backup test to a "null" device.  Backup to a null device uses the same NetBackup client processes as a normal mailbox backup, but sends the data to a null file on the Exchange server. This causes NetBackup to read all the data,  but instead of transferring the information to tape to be saved, it is sent to a null device. This process mimics the backup process and is an excellent test to determine the theoretical maximum possible speed of a backup since it eliminates any potential network or tape drive speed issues from the test. This test only looks at how fast the information can be read from the Exchange database.  

To test mailbox backups to a null device, go to a command prompt on the Exchange server, and change to the <install_path>\veritas\netbackup\bin directory.  From there, issue the following command, substituting the actual name of the Exchange server for the client name field:

bpbkar32 -nocont -clnt <client_name> -ct 16 Microsoft Exchange Mailboxes:\ > nul > c:\temp.out

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.


Level 6
Please read this thread: (If you use GRT backup)

Level 6
Which kind of backup do you use "Mailbox" or "Store" ?

Level 6
I recently looked back at some of the GRT test runs we have been performing for the past several months with Symantec and compared the times with the standard (non-grt) backups.  I found that the GRT backups took approximatly 10.6 times longer!

I'm curious though, how large are your databases?  There seems to be issues around roughly 70GB and up.


Level 6
Our tests are run with a 40GB database + 25GB database