Hi,
Overall...............
Normally a site will have one or more primary storage pools. These may
be colocated to improve the efficiency of restores, depending on the
site and its resources. These primary storage pools are copied to one or
more copypools. The copypools are normally not colocated to save on
storage resources. The copypools are checked out and sent offsite, and
their status updated as offsite after the data is added to volumes each
day. Then as the expiration process expires the data of the copypool
volumes that are offsite, they are returned to the site and checked in
and become scratch volumes.
>>> sunglee AT US.IBM DOT COM 02/11/2005 2:55:28 PM >>>
Hello,
I have a follow up question.
I see that you have 3 storage pools. Can you tell me what "COPY"
storage is
used for? is this one used like similar to Primary or are you making
copy
of Primary?
Primary ---> Copy----> Offsite (goes to offsite)
or
Primary ------> copy (goes offsite)
------->Offsite (goes offsite)
Sung Y. Lee
Sung Y. Lee
"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU> wrote on 02/11/2005
11:34:46 AM:
> Hi, all: I've got a question I've been wondering about, relating to
how
> foresightful TSM is in its' offsite reclamation. I'll spin an
example:
>
>
> TSM server 'SRV1' has three nodes
>
> NODE1
> NODE2
> NODE3
>
> It's got stgpools
>
> PRIMARY : collocated . Volumes named Pxxx
> COPY : non-collocated . Volumes named Cxxx
> OFFSITE : non-collocated . Volumes named Oxxx
>
> Daily incrementals happen on all nodes.
> Tapes go offsite every day.
>
>
> OK, given that scenario, we know that the vast majority of offsite
tapes
have
> a thin slice of data from all of NODE1, NODE2, and NODE3.
>
>
> --- Known scenario ---
>
> So when an offsite volume O213 passes the reclamation threshold,
the
server
> begins building a new offsite volume O501.
>
> It mounts PRIMAY volume P001 (with node1's data on it) and makes an
additional
> copy of those files from NODE1 that appear on O213, and are still
interesting
> to the server.
>
> Then it mounts PRIMARY volume P002, does the same for NODE2,
>
> Then it mounts PRIMARY volume P003, does the same for NODE3.
>
>
> Now, new offsite volume O501 is ready to leave on the next truck.
>
>
> --- Unknown scenario ---
>
> Now, what if O214, O215, and O216 all pass the reclamation threshold?
We
know
> the server's going to start building O502. Say it picks O214 to
begin
with.
>
> When P001 is mounted, will the reclamation copy files from -all- the
> reclaimable offsite volumes, only from O214, or what?
>
>
>
>
> I can see pseudocode something like:
>
> - Pick an offsite volume to work on
> - From that offsite volume, pick a first onsite volume to mount
> - From that onsite volume, determine all files wanted for
offsite
> reclamation. Copy them.
>
> This would be expensive in query time, but the alternative is a big-O
N *
M of
> tape mounts, which makes me shudder. But it would certainly be
simpler
to
> code.
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