Backup to tape slow processing rate

[mjboak]

Support case ID: 00874063

I am currently experiencing very slow processing rate during any backup to tape jobs.

The Processing rate is only running at 2 MB/s with the bottleneck pointing to the target.
Source 0%
Proxy 22%
Network 0%
Target 99%

Usually it is up around 60/70 MB/s

Any help would be greatly appreciated.

Michael

[veremin]

According to the provided statistics, it seems like the tape device can't write data any faster. Or you don't think it's not the case with your environment?

[mjboak]

I have looked at previous backup jobs and they were writing data to the same tape drive at 65 MB/s or more.

[veremin]

Sorry, missed the part regarding current speed. For some reason I though the current speed varies from 60 to 70 MB/s which is more or less acceptable performance, as to me.

Anyway, what product version you're currently at? Have there been any changes introduced in your environment (to backup server, tape server, tape library)?

Thanks.

[mjboak]

The product version is 8.0.0.917 and there have been no changes to the backup server, tape server or tape library.

[Dima P.]

Michael,
Thanks for the details. Could you please clarify how your tape device is connected to the VBR? Is it the remote tape server or direct connection? Thanks

[mjboak]

The tape device is a Tandberg StorageLoader LTO-4 with a SCSI connection to the backup server.

[Dima P.]

Got it. In addition, how the source repository is connected to the VBR? Thanks!

[mjboak]

The source repository is on a raid drive on the backup server.

[Dima P.]

Michael,
Thanks! I’d check the performance with disabled hardware compression/encryption if there were any, besides you could test the real throughput with native vendor’s tools – just to verify the performance is not somehow influenced by VBR.

In addition, check this post: New Features and Enhancements - Performance enhancements part. You can enable the Shared memory usage to tune the tape performance.

[mjboak]

Thank you all for your help. In the end I think it was a problem with the SCSI cable as my backups are now running at the usual 65 MB/s or higher.

[Dima P.]

Michael,
Thanks for the heads up! I always forget about the possible hardware failures – virtual world is almost perfect