Hi Cris,

Normally you will find that this happens when you do not run reclamation
on the tape. Your tape was full at one stage, but as your data expires the
percentage of valid data becomes less. Run reclamation on the tape and
this will solve your problem.
I assume you have a DLT4000 tape drive and you have compression switched
on on the ADSM client side.
The algorithm ADSM uses for compression is similar to the one that the DLT
drive uses. Your data is compressed on the client side, sent to ADSM and
then
when it is written to the drive the drive will try and compress the already
compressed
data. ADSM will only report the amount of data written to the tape and that
is what
you are seeing here.

Regards

Christo Heuër
ABSA Group
Johannesburg
SOUTH AFRICA
"Right now I'm having amnesia and deja vu at the same time.
I think I've forgotten this before."





>Question: We are trying to rationalize why ADSM shows our DLT IV tapes
>as full yet they are only 30-50% utilized and
>the Est Capacity is ~20GB instead of 40GB?
>
>Here is a sample of our tapepool status:
>
>
>
>Volume, Storage Pool,   Device Class,  Est Capacity (MB), Percent
>Utilized, Volume Status, Access Mode, Scratch
>------------------------------------------------------------------------
>------------------------------------------------------------------------
>-----------------------------------------------
>D50201    TAPEPOOL     DLTCLASS     18214.7                 59.3
>Full          Read/Write             Yes
>D50202    TAPEPOOL     DLTCLASS     18010.0                 55.0
>Full          Read/Write             Yes
>D50203    TAPEPOOL     DLTCLASS     18566.6                 45.9
>Full          Read/Write             Yes
>D50204    TAPEPOOL     DLTCLASS     18620.7                 28.7
>Full          Read/Write             Yes
>D50205    TAPEPOOL     DLTCLASS     18800.4                 9.9
>Full          Read/Write             Yes
>D50206    TAPEPOOL     DLTCLASS     20480.0                 6.7
>Filling       Read/Write             Yes
>D50207    TAPEPOOL     DLTCLASS     18450.5                 20.5
>Full          Read/Write              Yes
>
>Thanks -
>CR
>
>________________________
>Cris Robinson
>Senior Technical Analyst
>Desktop Services Technical Support
>Liberty Mutual Insurance
>603.431.8400.54837
>cris.robinson AT libertymutual DOT com