Link to home
Start Free TrialLog in
Avatar of cfox869
cfox869

asked on

Why would brand new LTO3 tapes hold less and write/read slower than old tapes in current inventory?

I'm using Backup Exec 11d (Rev 7170, HotFix 37, Svc Pk 5, HotFix 70 using BE drivers) and a Quantum Superloader3 w/ Quantum drive (ver 2181).  All new media (Quantum and Fuji) I use will give me "Media Full" between 232GB and 308GB while media created in 2009 will get 'full' between 438GB and 496GB backing up the same data using the same jobs.  My weekend backup (just over 1TB) should be using 3 tapes and now is up to 5.  One of my nightly backups typically (on old tapes) runs 4 hours. Last night on new tapes... 7 hours 20 minutes which ran over my next backup job start time.  I have xTalk logs for Device Health and write/read full tape on a 'New' tape.  I need to run write/read full tape on an old tape for comparison.
Any help, greatly appreciated. Thanks.
Avatar of Jon Scriven
Jon Scriven
Flag of United Kingdom of Great Britain and Northern Ireland image

LTO 3 tapes should be 400GB capacity (800GB using compression) so this is a bit of a strange one.

Probably worth updating the Quantum Superloader firmware.

Did you do an erase or anything on the tapes before you started using them?

I use Netbackup and LTO3, but tapes show as full at around 600GB.
I have just looked historically and some say they are full as low as 480GB and as high as 728GB (we use compression) - so if you halved those (assuming you aren't using compression), the range is pretty similar to what you are seeing.....
LTO2 = 200GB Uncompressed
LTO3 = 400GB Uncompressed

If you are now only getting 200GB on a tape are you sure they are LTO-3 tapes?

What does BackupExec think they are?
ASKER CERTIFIED SOLUTION
Avatar of Thomas Rush
Thomas Rush
Flag of United States of America image

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Avatar of cfox869
cfox869

ASKER

Update: Quantum is replacing the drive after reviewing the xTalk logs for Device Health and Full tape write/read on both "New Media" and "old known good media".

SelfGovern: Your assessment is correct.  "tape head that has been used to the extent of its useful life"  Thank you.

The attached file shows the tape capacity decline from March 2010.  And you can see the same decline from October 2008.  The tape capacity went back to 'normal' after the drive was replaced in Sept 2009.  



Date-and-Capacity-Page-2.jpg