L20 underwriting problem

[edwalsh]

Hello,

We have been having problems with our L20 Library which has 2 LTO 1 drives installed, we are using it with Legato Networker 6.1.
One of the drives has started writing anything from 64K to a couple of megabyte and then marking the tape as Full, I have had to make it read only.
The other drive also seems to be underwriting in that some tapes it will write a couple of meg and on others it will write 75gb.
We were getting between 100gb to 150gb per tape off these drives.
Sun and Legato have advised us to change the media which was new in 2002 and gets overwritten 4 times a year.
We are currently waiting for a delivery of new tapes to test.
Has anyone had a similar problem?

 

[tapedrivedoctor]

it sounds more likely to be the way you have your jobs set up in legato. Is the media set to overwrite the data or append. you could be just adding data to the tape all this time, and not realising you weren't overwriting the old data until the tape became full.

 

[edwalsh]

No, we do not append to the data. When we load them we re-label (erase) them.
They revolve around a 3 month period, we clone the important data.
I should add there is an L25 library an L1000 library and 2 standalone drives attached to this Backup Server as well as the L20. All the other drives are DLT.

 

[Pachtva]

Hi..

the problem here its with an i/o error in the scsi bus, because if this its a L20, only can be SCSI, also if have a SCSI / Fibre Router.

But if the software Legato found an error in the SCSI BUS when its performed a backup or restore, the manner in which LEgato protect the data its puting the cartridge like a "Full", in this manner any more jobs cant take it.

You have to review the configuration of the tape drives into L20, in the menu the L20 have an option in the drive configuration menu that said "Bus On: Off or On", if your tapes are in daisy chain conecction, this setting is ON, but if the cables are in differents ports of the HBA then have to set in "Bus On: OFF". The common of this error its the SCSI cables (check the pins of this) or the SCSI terminators. If its ok, clean the drives with the "clean tape", if does not works, call to your support or the warranty, this is a Hardware problem!!!! (i/o error)

 

[edwalsh]

Thanks for that Pachtva I will pass it on to our freindly on-site SUN guy and see if he can sort it out.
As a work-around I have made read-only the drive that seems to be the main culprit (which was replaced but is still underwriting), and have been deleting the tapes from the volumes database in Legato before labelling them.
That way it seems to write 100 - 150gig a tape, but only using the one LTO drive.
Thanks again for the reply.

 

[edwalsh]

Just in case anyone else gets this, after months of trying different things to resolve the problem the StorageTek Engineer replaced all of the cabling on the library and we are now back to writing Full 150gig average backups on both drives.
Thank God!