Duplicate to tape slower than straight to tape

[Douglas_Dahlber]

Performance question. Our BE server backups our main file server using B2D. We then duplicate the data to tape. Thru put during the B2D is great 1200mb/min. When duplicating to tape the thru put is 360mb/min. (which happens to be the max native non-compressed speed of the tape drive)

Here is the odd part. If I backup the same files straight to tape and not B2D the thru put to the tape is 500mb/min. I have comfirmed that all the jobs are set to use Hardware compression. The job logs confirm the jobs used hardware compression.

Is there some sort of extra overhead with BE reworking the catalogs that would reduce the thru put to tape? In theory shouldn't the files duplicate to tape as fast as the straight to tape jobs?


All the jobs run fine. No errors logged anywhere. No real problems just odd.

Setup:

BE server is a Dell 2850 - 2 2.8 Xeon, 2gb ram. 1 gb intel nic to file server. 1 dedicated gb nic on private VLAN to iSCSI REO 4000. All B2D files are sent to the REO. Tape library is an Exabyte 230 with two VXA-2 drives connected via Adaptec SCSI controller. BE is the latest with all hot fixes applied as of 8/15/06

File server is a Dell 770N - 2 2.4 Xeon, 2 gb ram. 1 gb intel nic. Files stored RAID 5 volume connected to a PERC4 controller. Remote agent is current as of 8/15/06.

[tejashree_Bhate]

Hello,

What is the Backup Exec 10.0 revision you are using?

You may upgrade to 10 d if you are not using 10d

Symantec Backup Exec (tm) 10d rev. 5629 for Windows Servers Installation Files

http://support.veritas.com/docs/279332

Symantec Backup Exec (tm) 10.1 (10d) for Windows Servers revision 5629 - Service Pack 1 - Includes Critical Security Updates

Symantec Backup Exec (tm) 10d (10.1.5629) - Device Driver Installer (20060615) - Includes Tape Driver Release (18) and Robotic Library Release (64) (Intel Only)

http://support.veritas.com/docs/284012



Are there any device related errors in the system event log?

http://support.veritas.com/docs/255501

Let us know the update

thanks

[Douglas_Dahlber]

I am using 10d. Build 5629 SP1 - HF 9,26,27,29,33.

No errors are logged by BE or in the system event log. The jobs run to completion and work when it comes to restoring files.

They are just slower than if I backed up straight to tape.

Question: When the Duplicate job sends the data to the tape from disk - what kind of is it streaming? Is it the individual files again or is like sending a bkf file? I know it recalculates the catalog files to reflect the new destination media. I just didn't know what type of data it is sending to the tape.

Thanks for checking back to quickly.

[Rucha_Abhyankar]

Hi Douglas,


Have you configured these backups and duplicate backups using a policy ?

If yes,delete and recreate the policy for test purposes.

[Douglas_Dahlber]

Nope. They are not creating using a policy. They are just done manually. Duplicate existing backup sets.

[Deepali_Badave]

Hello,


Perform the repair installation of Backup exec.

Please refer the following technote:
http://seer.support.veritas.com/docs/253199.htm

Regards,

[tejashree_Bhate]

Hello,

Please could you provide an update?

Thanks