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slow backup of VMWare servers

Created: 01 Nov 2012 | 7 comments

I have two VMWare ESXi 4.1 hosts, and am backing up the guests to tape on a physical server over a 1 Gbps line. The guests are all on direct attached storage. A couple weeks ago the backups on one host began to crawl. For example, a 20 minute backup now takes 5 hours or so. We are using Backup Exec 2012. This problem only occurs for the guests on one host, whereas the other host is completely fine. Both servers use the same switches. The server that is slow to backup is able to host the VMs without any problem at all, and the vSphere client displays no errors or anything other than "normal" for the hardware status.  Any idea what could be causing the problem?

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Lesta G's picture

I would suspect that the server or switch ports speeds are not matched and one is at half duplex and one is at full duplex.

what is the speed like if you copy a file from a VM on one host to the media server?

Regards
Lesta
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lmosla's picture

Make sure that if you have virus protection running that the path for the Backup Exec directory is excluded from the scan.

see for a reference on excluding Symantec Endpoint Protections scan http://www.symantec.com/business/support/index?page=content&id=TECH61909

hope this helps,

Vivek Jain's picture

If using only NBD mode, see if this makes a difference or not ~ http://www.symantec.com/business/support/index?pag...

And are you selecting via the ESX host or via the vCenter.. try switching around to see if it makes any difference... lastly, as LestaG mentioned earlier, do try to get a base as to what speed you get for a normal copy..

Jaydeep S's picture

Confirm if kb.vmware.com/kb/1007654 has been configured correctly on the ESX hosts.

ScotH's picture

Thank you for all the suggestions.  Here is what I found:

- The network adapters on the VM hosts are configured for 1 Gbps, full duplex, and the adapters on the guests and the switches are set to auto-negotiate.  This is true for both the server with the speedy backup, and the slow one.

- We have Endpoint 12, and it does not scan during backup.  Also, the files are scanned at modification, but not when accessed.

- Based on the NBD issue mentioned above, I specifically excluded that, but it made no difference.  I backup through the ESXi host, but not through the vCenter (not sure how to go through this). 

- As for MTU/Jumbo Frames, some adapters were set for 1500, but most have it disabled.  This is true for both the server with the speedy backup, and the slow one.

- As for file transfer speed, the server that backs up quickly transferred a file at 7 MB/sec, whereas the server that backs up slowly transferred it (oddly) at 11 MB/sec. 

lmosla's picture

What are the applications on the vms being backed up? Try recreating the job to see if there is was possible any corruption in the job.

ScotH's picture

A few different servers have been backed up, and I have turned off GRT to ensure the apps are not a source of the problem.  I have also recreated the jobs.