Pauses in Backup-to-disk jobs

[Mike_Kirda]

Greetings.

I've been trying to track down why something is happening. I've got a dedicated backup server that is set up to back up Server2 (with attached SCSI HD array) to a remote Dell NAS unit (Powervault 725N). Machines have Gigabit connections throughout, and the bandwidth is nowhere near capacity.

The backup-to-disk folder is located on the NAS unit, and the backup jobs run just fine. The issue is with transfer rates. I have seen jobs run at 400 - 600MB/min. The trouble is that this speed has been unacheivable for many months now.

What I noticed last night while watching the job is that the job starts slow, then speeds up drastically. I'm seeing transfer rates of 600MB/min. The job get to just over 1 gig AND THE JOB PAUSES FOR ABOUT TWO MINUTES. The average transfer rate goes down to about 200MB/min by this point - and I can see that not one byte has transferred for about two minutes. Suddenly, the job un-sticks, and starts up again. The transfer rate goes up again, this time to about 300 average. As the job reaches the 2 gig mark, again, stops dead for about two minutes. I continue to watch the same thing happen at 3, 4, 5 and 6 gig marks. By this point, the job is pretty much stuck at 200MB/min and stays this way for the rest of the job.

I'm looking at the job I started yesterday and the job is suddenly stuck at 268,662,543,816 bytes. I wait a minute or two and it starts up again...

What the heck is going on???
Anyone have a clue?

Regards.
Mike Kirda

[Ajit_Kulkarni]

Hello,

Please refer to the following technote which may help you in resolving issue:

What Backup Exec settings can be modified to reduce the amount of time it takes for a backup to run?
http://support.veritas.com/docs/249090

Regards,

NOTE : If we do not receive your intimation within two business days, this post would be marked ‘assumed answered’ and would be moved to ‘answered questions’ pool.

[Sheetal_Risbood]

As per our previous reply, marking the case as assumed answered and moving it to answered questions pool.

[Mike_Kirda]

Actually, no, it hasn't been answered.

This sort of canned response doesn't merit the moniker of "Tech support".

I was hoping somebody who knew what the heck they were talking about would step forward.

Regards.
Mike Kirda

[Mike_Kirda]

I will also add that, in the meantime, I have upgraded the processor in the NAS unit to the maximum that it will handle. Situation is still the same, and appears to be something in theVeritas software. In other words, this does not appear to be a hardware issue.

Regards.
Mike Kirda

[A_van_der_Boom]

Hi,

I see similar things with my Powervault 745N with also a gigabit interface. Sometime it is still performing my duplicate jobs when I start work and sometimes it is ready, like it shoud be.

When I simply copy something to the powervault the transfer speed is oke. So now I configured perfmon to log the NIC traffic to see what is going on.

Regards
A van der Boom

[Renuka_-]

hello Mike,

1. You need to check for any network issues in case of this haphazard behaviour.

2. Please do the same backup using Microsoft NT backup to isolate the issue.

3. and please get back with the results.

NOTE : If we do not receive your reply within two business days, this post would be marked assumed answeredand would be moved toanswered questions pool.