Verify = slooooow

[RedTech]

I'm sure that I'm the only one experiencing this (seems to be the trend lately).

The backup takes place fine, then verify takes sooo loong (abnormally). The backup and verify exceeds. I'm using Backup Exec 9.0 on windows 2000 server.

Anyone hear of this or experience this?

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[bowfonz]

As a rule I always disable the Verify. I know that's not much help for you, but I have found that Verify is more trouble than it's worth.

 

[tahoe2]

I agree. Even if Verify finds something bad, its not going to re-backup the file. Disable it.

Corie

 

[Cuba7]

Many tape drives verify on the fly, eg. DDS. Check the specs of your drive.

Cuba

 

[justin2000]

Yeah sure turn off verify it is a waste of time - unless of course you want to verify that the data has been written properly to the tape - verify can usually pick bad tapes or bad tape drives before they become too much of a problem.

For those of you who don't verify after a backup - suffer - when all your backups tapes are bad and you have to restore your server and you can't.

 

[bowfonz]

If you run test restores, keep a clean drive and replace your tapes annually whether they need it or not (and you should), there is absolutely no use whatsoever to use Verify.

 

[LaChimere]

Hi

I think that verify is something important.
Can you check if your are doing checksum. If you dont, that could decrease the spped of the verify. Verify needs to have checksum on the tape. the checksum option put checkpoints on the cartrigde. so the Verify process can proceed faster then

Le monde c'est de la marde!

 

[steveot]

For all that are with the not to Verify....I guess your data and job arent important to you. Test restores, clean drives, etc...all dont mean anything. Those are tests on one tape for a given period. Prove to us by Microsoft or IT standards "there is absolutely no use whatsoever to use Verify". Would you backup a database or exchange server that is worth millions of dollars , plus the per hour your company loss during the down time without a verify and not be able to restore it?. I would want a verify to prove to my boss that I wasn not neglegent or just plain ignorant. Justin is right on.... Call veritas with a restore problem and if your getting errors "Difference encountered in file data or media errors during the restore". If you cant prove you verified the data then your unsupported and best effort to restore or a long catalog and pray that you can pick up the data you need. Any Backup Software vendor will tell you the same thing.

 

[bowfonz]

First off, let's all just relax. I have an idea why there is a difference of opinion on this thread. There are two types of IT guys. There's the Network Admin working for a single company full-time, and then there's the Network Engineer out in the field working for hundreds of clients. I am the latter.

It seems to me that if I were the Network Admin working for a large multi-million dollar corporation, it would benefit me to spend the time, effort and expense to figure out why the Verify on BackupExec is giving me errors. So in this situation I agree with you about using the Verify.

But the IT guy in the field who is working for many small/medium size businesses and is charging his clients by the hour and most importantly, has end users changing tapes and monitoring the backup's success, cannot spend hours and hours each time the Verify errors trying to figure out why. New tapes, clean drives and periodic test restores. It's quick, it works and I've never had a problem. I have restored entire tapes that Verify has errored on and had no problems with them. So that is why I say Verify is of no use, because it is of no use TO ME. In the field, you can't always go with what MS or Veritas says or what is correct in some whitepaper, you go with what works.

So Verify is useful and important for some and not worth the effort for others, it just depends where you're coming from. Does this make sense?

 

[RedTech]

Man has work been killing me!


Yeah bowfonz , I'm the Network Admin in your scenario. Verify is an option that I cannot disable.

We are using a Cybernetics Library (15 tapes) which has a Sony 700 SDX Tape drive. We have brand spanking new tapes. We clean often.

What's of real interest is that this doesnt occur all the time. With either a small 20gb backup or a full 285gb backup we will see the verify finally fail after trying for 12 hours (our threshold). We may see this on a couple tapes... then all of a sudden everything will just work smoothly. Now mind you these are scheduled backups and nothing (configuration wise) is ever changed on the server or the backup software.

This is why it blows my mind.

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[RedTech]

LaChimere,

yes we have the checksum option ticked.

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[justin2000]

bowfonz

what happens when the customer finds out that you have configured to turn verify off - and they can't restore their data now because verify could have told them ages ago that something was wrong with the tape?

and you can say it won't happen, but one day it will...

 

[bowfonz]

Maybe I can put it another way so you'll understand. Verify is not required. Not by me, not by my clients, and certainly not by law. It is an OPTION. I choose to turn it off because the situation dictates it. My clients trust my judgement and the decisions I make. I take other measures to insure that they have good backups (test, restores, cleaning the drive regularly, replacing tapes annually). And I don't rely solely on the backup tapes either. I have mirrors, raids, ERDs, and in some cases xcopies of data. And you make it sound like there is only one tape. Most of my clients have 14 tapes or more with a full daily backup on each one. I've seen bad tapes before, but I've never seen 14 bad tapes in a row.

I setup the backup my way. I am the IT guy, not the client. They hired me to exercise my judgement in their best interest. In my experience, and in my line of work, Verify is problematic. I don't have the time and the client doesn't have the money for me to troubleshoot it. So I turn it off. I would rather answer the question of why I don't turn Verify on (which would never come up, btw), than to answer the question why I'm billing an extra $1000 a month just to troubleshoot the daily Verify errors.

I'll say it again, I don't think that Verify is bad. It just requires a lot of attention. I cannot be at every client site every day just to troubleshot the Verify, that's ludicrous. I HAVE to turn it off.

Can I explain it any other way?

 

[tahoe2]

Thanks, Bowfonz. That was my point too. With annual replacements, monthly test restores and 6 or 14 tapes each with full backups (I also back up the system state data every day) My clients do not need the added expense.
Also, I use the Ultrium tape drive which is pretty much idiot proof. It has a built-in monitor that lets the user know when to run the cleaning tape and if there is a problem with either the tape or the drive.
It works for me.

Corie

 

[justin2000]

I wasn't going to venture into this debate anymore.. but.. I have to tell you a story..this happened quite recently as well..

Customer (small company, 25 users, 1 server, exchange, AD, file/print server) was doing backups, with no verify's.
They call me in because their server has crashed and the company they use can't get the data back and they have been told not to come back.

I have a look - 2 hours into it - found ALL their tapes have CRC errors on there, thats 10 tapes - and guess what I can't restore them at all - they now want to take the tapes to a data recovery place to get the data back - initial costs to get this data back - around $30k - and it will take around 1 week.
This is not the only cost this company is currently paying for because of the downed server..
Now these tapes are 4 weeks old.. yes you heard right 4 weeks old - they have each been used twice... they were just replaced because they got a new tape drive, so new tapes were bought as well, the old tape drive was broken beyond repair - so they threw the old tapes out as well..
Anyways.. to cut a long story short..I did some tests on the tapes and found that the tapes had bad blocks on them, and looking deeper into the files, there were alot of files with bad checksums.
The backups however were completing successfully with no errors..
Now if only they had used verify on their backup jobs.....

 

[Igore]

This is all very nice and a lively debate on the merits of verify, but has not addressed the question significantly.

I haverecently been experiencing odd verify behavior. I have a series of backup that run on a quantum 160/320 SDLT drive with BENT 8.6 on 2000 server. It has run happily for over a year. Now I have several of the jobs that suddenly take 2X and 3X as long as before. I compare logs and it is the Verify that is taking twice and 3X as long as before. They ultimately succeed, without errors. Any thoughts on what would cause the change.

No changes have been made to the config of any of the jobs. There are 4 separate jobs that run each night, so I can separate the Novell, Notes, File server backups. First the Notes job started. I had to go to Differentials just to reduce the time. then things were OK. Next the File server job started running over. Now the Notes Differetial has started taking 4X as long as the day before.

To weigh in on the debate. I have worked both sides (Outside Consultant, and now In-House Engineer), and I see both sides of the aurguement.
I, too, clean drive weekly, and tapes are well within manufacturer specs for usage. DLT tapes are good for between 1 and 8 million read/write passes before they should fail, and when one does, the manufacturer replaces. They are, for all intents and purposes, a life-time guaranttee.

Most drives do a write-read exercise on the fly to make sure that when it writes a 1 the read head sees a 1 on the tape. On the other hand, notification about imminent tape failure is nice. 4-5 times that my verify reported tape errors, a firmware update on the drive cleared it up. The fifth time Quantum replace the tape.