Backup Exec Database Performance Tuning

Tuning changes from default settings to improve performance of backups, duplicate and restore jobs

This will mainly improve on the backup performance, but improvements should be seen with duplicate jobs and restore jobs as well. The more jobs that are running using this device and the more data that has been deduplicated the better will the benefit be.

Increase shared memory buffer


Default is 32M, Increase in increments of 32MDo not increase to more that 4x default size. If change has little or no effect return it to default setting. This tuning is less efficient with large memory setting on Windows servers than what would be the case on Linux servers as Windows will use the OS caching and a smaller shared memory buffer setting will give the better performance. A too large shared buffer setting will have a detrimental effect on performance. Proceed with great care and monitor performance and system resource usage closely. Do not use Notepad to open the .conf file and make the edit, use Wordpad or similar and make a copy of the .conf file before editing! For the needed service restart to make the changes take effect see important note at the end of next section!

Rehydration performance

This will mainly improve on the performance for restore jobs and duplicate to non optimized device type jobs (tape, RDX)

\Program Files\Symantec\Backup Exec\contentrouter.cfg


Change from default 1 in increments of 1 and do not go higher than 4


Default size = 65536     (64K)

Change to   = 1048576 (1M)

Setting uses bytes. Do not increase this setting above 1048576 (1M)

Do not use Notepad to open the .cfg file and make the edit, use Wordpad or similar. Make a copy of the .cfg file before editing!

! Important ! For all above mentioned changes to the settings to take effect the Backup Exec services will need to be restarted. Use the services manager and start all Backup Exec services including the deduplication services. Before restarting the services check that the deduplication storage device maintenance is not running (queue processing). It runs at 12:20 and 00:20 every day. Run below from cmd and verify that the status for Busy and Pending is “no”.

C:\Program Files\Symantec\Backup Exec>crcontrol –processqueueinfo
Busy   : no
Pending: no

General performance settings

  • Use 64Kunit allocation size and 64K stripe size on the volume used for the Deduplication Storage Device
  • Use the highestpractial number of disks you can use to obtain the volume size needed for the volume used for the Deduplication Storage Device
  • Set Power options in Windows to High Performance
  • Set fixed speed and do notuse any type of auto negotiate, this applies to Fiber, iSCSI and Ethernet. This applies Deduplication Storage Device path (except ethernet) and for data transfers for the backup/restore jobs. For the NIC’s used on the media server set the Max Coalesce Buffer to and the Max Transmit/Send buffer to max
  • Understand the RSS, NetDMA and TCP Chimney settings and test what gives better performance and what does not. Should be disabled for 1GB NIC’s. See Microsoft KB’s 951037 & 912222. If there is no difference in performance with any of the settings enabled or disabled consider leaving it as disabled


Leave a Reply