Throughput rate question

[TysonLPrice]

I'm new to the Veritas backup product. It was installed by a third party support group. My question is generally the backup runs in 5-6 hours. Ocasionally (every 5-6 days) it runs for over fifteen hours. Comparing the job log of a short run versus a long one and the only real difference is the throughput rate. For example for the same set of files:

Average night:
2,000,000,000,000 bytes in 11 minutes and 14 seconds
Throughput rate: 173.8 MB/min

Slow night
2,000,000,000,000 bytes in 1 hour, 1 minute, 35 seconds
Throughput rate: 31.7 MB/min

I see one night is slow consistanty for a particular tape and I plan on replacing it but this is not always the case. There are no error messages other then files skipped but they are the same for both runs.

Any suggestions on how to researh this? Can dirty tapes cause this?

Thanks in advance!

 

[ih8MSos]

On the slow nights is there maybe a sql process such as ms sql backup running during your backups? or some other third party nightly report running? Have you tried to use network monitor to find the bottle neck. is it always the same servers? do you get reports of the backup agent not being present?

 

[SQLBill]

Is there something else happening on the system on that night? (are you the DBA or the SysAdmin?, if you are the DBA, check with your sysadmin to see if they are running anything at that time). It might be a bad tape, but I'm really thinking it might be something else happening at the same time and using some of your systems resources (processor power).

-SQLBill

 

[TysonLPrice]

1. "are you the DBA or the SysAdmin?"

No I'm a programmer. I'll check with our DBA but I'm pretty sure nothing like that runs during the day and when the backup is having a slow run it is still grinding away way past nightly processing.

2. "Have you tried to use network monitor to find the bottle neck"

I'm not familiar with that tool but I'll start looking into it. This is a small business with only a part time DBA and myself.

3. "Is it always the same servers?"

Comparing the logs from a slow night to a normal night they are practically identical except sometimes different files are skipped. Everything points to the throughput rate.

Thanks for the responses so far. I'm going to keep the post active hoping for more input.