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
