Huge speed variations in disk to tape copy jobs

[Artegic]

BackupExec 2012 Rev. 1798 64 Bit with Service Pack 3 running on Microsoft Windows Server 2008 R2 Standard, backing up a Windows 2008 file server and Active Directory domain controller, an Exchange 2010 server, a Windows 2008 terminal server, a Linux server, a VMware ESXi host, and itself to disk deduplication store and copied from there to LTO-5.

In this setup I'm experiencing huge speed differences with the copy jobs from disk to tape. For example, these are the last couple of tape jobs in the log:

- 0.3 GB/min (1 hour for 22 GB) from the backup server itself

- 0.7 GB/min (9 hours for 350 GB) from the Exchange server

- 1.2 GB/min (5.5 hours for 370 GB) from the ESXi server

- 3.3 GB/min (34 mins for 100 GB) from the backup server

- 1.6 GB/min (4 hours for 370 GB) from the ESXi server

- 0.6 GB/min (11 hours for 350 GB) from the Exchange server

- 2.8 GB/min (2.25 hours for 340 GB) from the ESXi server

There's no corresponding variation in any of the performance parameters on the backup server. (CPU load, RAM usage, disk activity)

What could be the reason for that kind of variations? How can I find out what's holding up the slow ones?

aTdHvAaNnKcSe,
Tilman

[Colin_Weaver · Accepted solution]

Do you see massive variation from day to day for the same backup set being duplicated?

Reason for question is as you are using Deduplication then it is probably the rehydration process for the duplicte which is causing the speed differences i.e. an Exchnage datastore uses different resources to re-hydrate (and catalog generate) than a set of files from the file system or a VMDK from a virtual machine

[Artegic]

Copies from the deduplication store to tape are consistently slowest for backups of the Exchange server, but still with noticeable variations:

- for full backups, from 0.46 to 0.65 GB/min

- for incremental backups, from 0.17 to 0.46 GB/min

Copies for backups of the ESXi host are considerably faster:

- for full backups, from 1.2 to 2.8 GB/min

- for incremental backups, from 0.5 to 0.6 GB/min

Windows file backups range in between, with wider variations:

- for full backups, from 0.8 to 3.3 GB/min

- for incremental backups, from 0.3 to 0.8 GB/min

[Artegic]

For comparison, tape to tape copy jobs run at 8 GB/min consistently.

[Artegic]

So I guess I just have to live with copies from deduplication store to tape being incalculably slow.

[CraigV]

...it's like that with most applications unfortunately, unless the deduped file out is in a single-file. Then backing up to tape isn't an issue.

Thanks!