I am by no means an expert in TSM. I did manage mainframe HSM
environments for many years (and still do, although it doesn't need
much tending to). And I dabbled with TSM for a few months. But from
what I know, yes, I think you are right about reclaim (it is called
recycle on the mainframe). It moves unexpired data from one tape to
another, thereby "freeing up" the space on the source tape that was
holding expired images.
Cheers
Dean
On Wed, Sep 29, 2010 at 10:44 PM, Mark Hickey <Mark.Hickey AT hds DOT com>
wrote:
> I knew someone would pull out some niche backup product from some tiny
> vendor to hit me in the head with….:-)
>
>
>
> This is the last I thing I will add to the discussion, as it is a bit
> off-topic, but for my own curiosity…
>
>
>
> Dean, are you talking about reclaim? Because I don’t think that is exactly
> the same thing, though some might argue it is just semantics. If I
> understand correctly, reclaim copies unexpired images off of partially full
> tapes onto partially full tapes to increase both the number of full tapes
> and the number of empty tapes based on a threshold of unexpired capacity.
>
>
>
> If this is what you are talking about, then while it may in the end support
> some of what Adrian is doing, it is not what I was referring to. I was
> saying that I don’t think any backup applications notice an expired image in
> the middle of a tape, mark the tape used by that image as available, and
> then write new images on that same space on that same tape.
>
>
>
> Please help me understand TSM’s capabilities better if I am misinformed
> about this.
>
>
>
> Mark
>
>
>
> Dean wrote:
>
>
>
>> IBM does tape recycling, and has for decades, first on the mainframe, and
>> TSM is heavily based on the same concepts as HSM on the mainframe.
>
>> They even called it "recycle".... F DFHSM,RECYCLE ALL P(30) EX
>
>
>
>>It means you can mix up your retentions on a single piece of tape media,
>> but it also means you have to dedicate a good proportion of your tape
>> hardware/time to looking after the recycle process (ie - basically doing
>> tape-to-tape copies every day to filter out the expired data).
>
>
>
>> There are pros and cons.
>
>
>
>> Sorry, I have nothing to add to what Mark has said, other than to call out
>> his "no vendor does it" :)
>
>
>
>
>
> Mark
>
>
>
> Mark Hickey
> Principal Technical Consultant
> HITACHI DATA SYSTEMS
> 62 Beach Road
> North Weymouth, MA 02191
> O 781.331.3508
> C 781.254.6441
> mark.hickey AT hds DOT com
>
>
>
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>
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