Backup failing - VERITAS

Hunter_Thompson

Hi everyone. Not sure if I am posting in the right place, sorry if not.

I am having some problems with a backup job on Veritas Backup Exec. One failed backup a week for past 4 weeks.

Failed backups =

20/08/2007 - Error : a00084af - The directory or file was not found, or could not be accessed.
14/08/2007 - Error : a00084af - The directory or file was not found, or could not be accessed.
10/08/2007 - Error : a00084af - The directory or file was not found, or could not be accessed.
07/08/2007 - Error : a00084af - The directory or file was not found, or could not be accessed.
01/08/2007 - Error : 17 - Data error (cyclic redundancy check).
26/07/2007 - Error : a00084af - The directory or file was not found, or could not be accessed.
19/07/2007 - Error : a00084af - The directory or file was not found, or could not be accessed.
13/07/2007 - Error : a00084af - The directory or file was not found, or could not be accessed.
09/07/2007 - Error : 17 - Data error (cyclic redundancy check).

I suspect a bad tape - seems to be almost same day each failed backup. Called the server tech, asked how many tapes they have - they have TWO weeks worth, and have been changing them every morning, they confirmed they are using the right tapes.

The error: "Data error (cyclic redundancy check)" is reported in the Backup Exec job log during a failed backup/verify operation

Veritas documentation on this subject suggest dirty heads or faulty medium or faulty hardware (tape drive). http://seer.entsupport.symantec.com/docs/192216.htm

The fact it is one day out of the week kind of cancels the theories of dirty heads or faulty hardware from my mind, but will try to organise it. Any theories / suggestions on how to figure this out?

Thanks!

primesuspect

Tape drives NEED to be cleaned, there's no way around it. Ask your server techs the last time they ran a cleaning tape through it.

Hunter_Thompson

Yeah, I figured that cleaning the heads may help - will get them to do this today.

But wouldn't dirty heads mean once the head is dirty, all subsequent backup attempts will fail? This is why I am confused - the backups have 10 tapes for a 2 week cycle. It seems one or two backups a week fail - with no pattern. If dirty heads were to blame, surely all backups after the dirt has been put on the head will not work?

Thanks for the advice, here is hoping cleaning the drive may help.

Hunter

primesuspect

There is no rhyme or reason to tape errors when dirty heads are involved. Clean the tape drive and then we'll see if we need to go on from there

stoopid

primesuspect wrote:

There is no rhyme or reason to tape errors when dirty heads are involved. Clean the tape drive and then we'll see if we need to go on from there

He speaks the truth.

Other possibility are worn media. Even with a 2 week tape cycle the tapes could get worn out in a year's worth of use. If the drive's old it may not be keeping the exact proper tension either which, in addition to any dirt on the heads, can cause data errors.

I've seen DLT backups work fine for a while then sudden start throwing these errors. In one case the drive was going bad and we spent countless hours narrowing it down to that cause, in the other it was a windows / driver update that required a patch from veritas/symantec we had not installed. Most of the time it's just bad tapes or a dirty head.

Hunter_Thompson

Well, as much as I don't want to believe it is a dirty head problem, it would be silly to try any other troubleshooting or diagnostic tests without out first going a pass of cleaning tape. BTW, the past two days have been backing up and verifying without incident. Last failed backup was Monday.

Let's sit back and wait for the next fail.

Hunter_Thompson

Cleaning tape passed through unit - still failing backups. Now trying to recreate all the backup sets.

mtrox

I agree with all that's been said. In my experience, tapes never last more than a year to a year and a half before they start failing. I've solved a few Veritas problems by chucking the tapes.

Hunter_Thompson

Hunter_Thompson wrote:

But wouldn't dirty heads mean once the head is dirty, all subsequent backup attempts will fail? This is why I am confused - the backups have 10 tapes for a 2 week cycle. It seems one or two backups a week fail - with no pattern. If dirty heads were to blame, surely all backups after the dirt has been put on the head will not work?
{/quote]

Is anyone considering the fact that it is NOT the same tape failing??? You telling me to go buy 14 new tapes? Based on what?

I think it has something to do with the backup set. I am going to recreate the set and see if I get improvement. Thanks for the posts.

mtrox

Hunter_Thompson wrote:

You telling me to go buy 14 new tapes? Based on what?

Yea I really am. Based on experience. I know they aren't cheap, but neither is your time. And a new tape drive is really expensive.

You really should run the head cleaner tape every week or two. If that doesn't solve your problem, then new tapes are in order. How long you had those tapes running 26 times per year?

Hunter_Thompson

Well the client is not going to be impressed everytime we have backup problems the first thing we say is buy new tapes.

The tapes in question are but a few months old.

Ran the cleaning tape through the unit 2 days ago and have not had a fail since. When we get through 2 weeks without a fail, I will claim success. If not, I will suggest new tapes...

mtrox

I didn't know they were that new. That would be odd. Now I'm swinging back to the head cleaner.

Hunter_Thompson

mtrox wrote:

I didn't know they were that new. That would be odd. Now I'm swinging back to the head cleaner.

Cleaned the heads several days ago. Had good backups for a few days, but now they are failing again.