Weird problem with LTO4 Tapes

[Theartemis]

Hi everybody,

Since a few monthes, we have a problem with new LTO4 tapes.

Here is the config : Backup Exec 12.5 on Windows Server 2K3 connected to a IBM Ultrium 3580-TD4 LTO Drive (SAN) mounted in a Dell Powervault TL2000. For many years, we've using using HP LTO4 RW tapes (C797A4) without any problems.

In december 2011, i ordered 10 HP LTO4 RW tapes (C797A4, the same that were used) to replace older tapes.

After a couple of days, i noticed that backup jobs were taking a longer time than usual only on the new tapes (Verify was doing at 200~300 MB/Min instead of 6000MB/Min). Also on the new tapes, i noticed many soft read errors (3000 after five days).

So i posted on this forum to find a solution, it appeared that the tapes was disfunctionnals. My supplier tool back the tapes and sent me new ones. After a few days, the same symptoms appeared. I told myself that it was a HP factory problem so last week i ordered Quantum LTO4 tapes (different supplier).

Here is the result on these new tapes :

- Backup at ~3000MB/Min

- Verify beginning at 5000MB/Min then dropping at 200~300MB/Min after a couple of seconds.

So i stopped the job and noticed 21 soft read errors on the tape.

The strange thing is that if i re-use old archived tapes, everything is fine, i've got this problem only on new tapes.

I really don't understand what is happening, here is the procedure i follow to add new tapes :

- Unwrap the tape

- Stick the barcode on it

- Insertion in the medial library

- On BE Server, i run an inventory job

- Then i label the new tape

- Finally, i add the tape to the correct media set

I'm really becoming crazy about that, if someone has an idea, my ears are wide opened.

Thanks, 

[ZeRoC00L]

Are you sure this only happens with the new tapes ?
Maybe a configuration change or update has caused a slowdown in backup.

Can you try an old tape (one that was 'fast' in the past) and see what the speed is ?

[pkh]

What is the format of the barcode label that you use?

BTW, when you use barcode labels, you don't have to do inventory.  A scan is sufficient and it is very much faster.  Also, you don't have to label new tapes.  BE will label them according to the barcode label during the first overwrite of the tape.

[Theartemis]

I've already tried this with ten "normal" old tapes and i've been backuping on these since 2 monthes without speed problems.

Barcode are 0000XXLU or 0000XXL4, same format as these :

[pkh]

You should not be using the labels with the LU suffix because these are for LTO4 WORM tapes.

[Theartemis]

I noticed this last week, my ex coworker labelled all the tapes by using 00000XXLU. This don't seem to affect backups but as i don't have 00000XXLU labels anymore i used a 00000XXL4 for the new tape.

[Theartemis]

So i tested another new tape, labelled 00002L4, i added it without making an inventory and ran a backup job. Again verifying is very slow.

I also tested a restore from one of the new tapes and it was very slow too.

Edit : It seems that my last option before calling Dell Pro Support is to upgrade Library and Drive firmware.

[Theartemis]

I updated both library and tape drive firmware then i erased new tapes (long erase), so far i've made a couple of backups/restores and read rate seems to be normal.

I just have a problem since library update, 

I think it's just a firmware bug because media attention led is not enlightened on the library and inventory is ok on RMU.

[ZeRoC00L]

Is autoclean enabled ? Then this error can appear if no cleaning tape is found in the library.
Just disable autoclean.