Back Up running slow

[raypedong]

I have an HP Storageworks Ultrium 960. I must suppose to backup a 160 GB size of file but it take me 2 days to backup. Any possible solution is much appreciated.

I use also the l&tt software to verify my installation it seems that my installation are ok except for this two lines:


Drive Performance Test :

Drive Performance test passed.

Drive performance is constrained. Check HBA and cable configuration. Also try another tape and clean the drive.
Measured native transfer rate is 72MB/S, 45% of the maximum See www.hp.com/support/pat for more information.



System Performance Test :

System Performance test passed

If you are backing up from a local disk system, then the backup performance will be seriously constrained by the speed at which data can be obtained from the disk(s).
See www.hp.com/support/pat for more information.

[D Lancaster]

What backup application are you using?

[Richard Bickers]

Wow. That's around 1 MB/S. At least you've verified that the HBA, cabling, termination and drive will go at 72MB/S which although isn't ideal certainly isn't your bottleneck.

You should check that the source data rate is reasonable using the system performance test in LTT. I hadn't realised the actual value isn't reported in the Install Check (have to fix that) but with the main tool you have more control over the data you are reading and visibility of the results. It can be across the network for instance.

Seems unlikely your source data would be restricted to 1 MB/S but you should at least find out what it is. This is often the bottleneck.

1 MB/S takes some doing though. Are you sure there's nothing else going on at the same time like a screen saver, virus scanning, dynamic virus checking (on every read/write), etc.?

You could pull a LTT support ticket at the end of the backup and post it to this thread. That may give us a few clues.

[raypedong]

i am using veritas backup exec version 10.

Actually, the situation like this, i have 3 hdd to backup one is scsi where the OS installed and the other two is ide hdd where most of our files reside. The resource order is scsi then the two ide drives.

once the backup started it has a job rate 2048 mb/m it is consistent until the end of the scsi drive, once it start backing up the ide drive, the job rate slowly drop down until it reach to 101 mb/m until the job is finished.

I also enable "on access scan" in my antivirus, is there any problem with this?

I pull a ltt ticket for the next back and will post it here. This is really insane backing up those files in more than your expected time with a hogh-performance backup drive.

Any helpful suggestion or violent comments are highly appreciated

Thanks & BR

rp

[raypedong]

Hi,

i attached my support ticket. I think my rsm cause the problem, i already stop the rsm service and will get back to you soon if still the problems exist.

thanks and regards

[Richard Bickers]

Had a quick look at the ticket. A few things stand out:

* RSM is on, as you say. Should turn that off
* There are bus resets showing up. That might be caused by the RSM. These will be very disruptive. (See event log under drive history with more details set).
* The drive does show around 6MB/S on previous backups (drive performance, more details level). That's not great but still quicker than 1MB/S! Something not quite adding up there.
* Data compression is turned off in the drive. That's controlled by the app - should not be using software compression (which will be slow...)
* Your HBA is capable of 160MB/S - not your problem!

Couple of things to do:
* Turn RSM off
* Set your app to use hardware compression on the drive - not software
* Run the LTT system performance test (backup pre-test) to measure the data rate of your source data. Probably a limiting factor - may be around 6MB/S?
* Try another backup and pull another ticket. Post if you want us to take a look.

Good luck. Richard.

[Richard Bickers]

One more thing seems odd. If you look at the data written to the current tape (drive health->write->current tape ) you'll see 65.7GB written but if you look at the amount of tape used (loaded tape->Cartridge usage->Native capacity used) it's almost exactly 1/3 of that. I did see a rewind or two in the history so maybe there's a lot of retrying going on from the app's point of view.

That might add up with RSM getting in the way. If that's causing resets and the app is seeing the backup go bad - so it retries - then it's going to take a very long time to get that data onto tape.

Fingers crossed turning RSM solves the problem.

[raypedong]

Hi Richard,

attached herewith another ltt ticket. i also attached last backup log file for your diagnostic.

i am not really satisfied with my back-up performance. I only have a througput of 109 MB/min for the ide drives while more than 1 gb for scsi drives which is not normal, i think.

could you please advice some hints?

thanks and regards,

ray

[Richard Bickers]

The page at http://www.hp.com/support/pat is what we recommend for general performance advice. Worth a look at this point.

In general the bottleneck is likely to be
1) The source data rate
2) The HBA/cable/drive
3) The application

Your testing has shown (2) is cable of 72MB/S which isn't perfect but not the problem here.

I'm thinking (1) is your limiting factor. Have you tried the LTT system performance test yet? That will allow you to read the data you're backing up off the source disks and measure that data rate independently.

I'm also suspicious of (3) having seen it write 3x to the tape than is *needed*.

Start with (1) and see what you get. I did also notice from your log that backups at night go more slowly than backups during the day (OK, the data sizes are very different) but do watch out for screen savers, virus checkers etc launching at night. I've noticed some virus software checks every file it touches which is very slow - need to turn that off before running your back up.

You can experiment with these using the system performance test.