--> Only if you expire your backupdata after one day

Yes, but this was intended to be an example to illustrate, not a real-life
case.

--> full is full ...

"Full" in TSM means volume reached end of tape. When this happens the
volume changes from "filling" to "full", estimated capacity is updated
with actual ammount of data written on the volume.

--> and this number must be 100.0

If is fixed value (be it 100 or not) it will give us no information at all
and should not be displayed. Pct. utilized is the ratio of "current /
(current+expired)". It is updated whenever data is written to the volume
or after expiration. Data write changes "current" component while
expiration reduces "current" and increases "expired".

Only if *all* data on the volume is not expired when it reaches end of
tape and becomes "full" then the ratio will be 1.0 (100%). My volumes are
usually slightly less than 100% (97-99%) in the collocated pool because
tape does not get full in one day. There are always few files with too
many updates (which got expired).
If volumes are constant at 20-30% utilization when "full" I would say
lower capacity (and cheaper) technology might be used. Or heavy
reclamation should take place.

Zlatko Krastev
IT Consultant






Henk ten Have <hthta AT SARA DOT NL>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
25.11.2002 17:05
Please respond to "ADSM: Dist Stor Manager"


        To:     ADSM-L AT VM.MARIST DOT EDU
        cc:
        Subject:        Re: tape become full in 21 percent.


On 25-Nov-02 Zlatko Krastev wrote:
> Consider following scenario:
> 1. you backup say 40 GB
> 2. next day you backup 40 GB of which 35 GB updated - 35 GB from step 1
> expire.

  Only if you expire your backupdata after one day.

> 3. perform step 2 for four days.

  Who will expire his backupdata after one day?

  And compression has also nothing todo with Pct. Util., full is full and
  this number must be 100.0, and at least you must see an Estimated
Capacity of
  100/200Gb, or if client compression is on and the data is good
compressed,
  you normally will se the native size of the tape as Estimated Capacity.

  Cheers,
  Henk ten Have