In comparison to NetBackup 7.1, the backup performance of Windows Incremental jobs with NetBackup 7.5 / 188.8.131.52 is noticeably reduced. This can be observed with either Cumulative or Differential Incremental schedule types.
Not all NetBackup clients will experience the same level of performance degradation; however, some jobs have observed a performance reduction by a factor of up to 5 times.
This issue is aggravated by a large number of files - with only a few files changed for the INC to pick up.
The wider the gap, the "slower" the performance.
Logic implemented for the Accelerator feature (new in 7.5) introduced some I/O overhead which causes performance degradation.
This logic is used regardless if the Accelerator feature has been enabled or not.
Additionally, at logging level General 2, the bpbkar log at NetBackup 7.5 / 7.6 can be significantly larger for the same data-set when compared with the bpbkar log at General 2 with NetBackup 7.1.
The formal resolution for this issue (Etrack 3210524) is included in the following releases:
- NetBackup 7.5 Maintenance Release 7 (184.108.40.206)
- NetBackup 7.6 Maintenance Release 2 (220.127.116.11)
More information on these releases can be found in the Related Articles linked below.
In-house testing of a client machine with roughly 3.5 million files. Only 45 thousand files have changed.
A NetBackup 7.1 INC schedule would back this up in 35 minutes.
A NetBackup 7.5 INC schedule would back this up in 2 hours, 30 minutes.
Note: Times will vary depending on NIC speed and Disk I/O speed and Processor speed.