ADSM-L

Re: progressive backup vs. full + incremental

2003-03-07 07:05:28
Subject: Re: progressive backup vs. full + incremental
From: William Rosette <Bill_Rosette AT PAPAJOHNS DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Fri, 7 Mar 2003 07:01:59 -0500
If you have 2 tapepools (primary) will 1 be collocate and 1 nocollocate?
and what happens the next day, does TSM pick up another 20 tapes for daily
backups?  On the question of the copypools (secondary) I understand this is
for restoring the tapepool, but in our case it is also used for DR and DR
must be up in 48 hours.  I can't have 121 tape mounts at DR for 1 node yet
alone the 9-11 we bring up, not a lot but can be with the time constraints.
And no not all my primary is disk.  Is there an easier way of showing just
primary or just secondary pools?

Thank You,
Bill Rosette
Data Center/IS/Papa Johns International
WWJD


                                                                                
                                                             
                      GUILLAUMONT                                               
                                                             
                      Etienne                   To:       ADSM-L AT VM.MARIST 
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                      03/07/2003 03:51                                          
                                                             
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Ok, now I understand what you meant. One solution would be to have two tape
pools : one containing 20 tapes for you 50 clients, and one with 1467
volumes for the rest. If you don't want collocation for all your clients,
it is the only solution I can imagine. But still it is not the diskpool
which is collocated but the tape pool.

But I still have a question : are your primary pools all on disk ? you are
talking of copy pools. I don't think collocation is very usefull for copy
pools as they are only used in case of the failure of the primary pools. So
I think it is acceptable to have a slow restore time in this case as it is
very unlikely (I mean having either your client and the primary pool having
a problem at the same time)


Etienne GUILLAUMONT
e-mail : etienne AT rgb-technologie DOT fr

RGB Technologie
Parc d'Innovation, Bâtiment PYTHAGORE
11 Rue Jean SAPIDUS
67400 ILLKIRCH
Tél :  03 90 40 60 60
Fax : 03 90 40 60 61



                    William Rosette
                    <Bill_Rosette@PAPA        To:     ADSM-L AT VM.MARIST DOT 
EDU
                    JOHNS.COM>                cc:
                    Sent by: "ADSM:           Subject:     Re: progressive
                    backup vs. full + incremental
                    Dist Stor Manager"
                    <[email protected].
                    EDU>


                    06/03/2003 20:56
                    Please respond to
                    "ADSM: Dist Stor
                    Manager"






Now back to my original question of:

How do you get a disk pool to go to a certain amount of tapes without the
other disk pools messing them up?


Let me try and explain.  I currently have my

 Maximum Scratch Volumes        1487
 Allowed


in my Copypool.  Are you saying to change this amount to 20 and then let
the 1 disk pool put 50 clients on the 20 tapes.  I have 3 disk pools, what
about the other 2 nocollocated pools, what do they use for scratch tapes?
(messing up)

Thank You,
Bill Rosette
Data Center/IS/Papa Johns International
WWJD



                      Chris Murphy
                      <cmurphy AT IDL DOT STAT        To:
ADSM-L AT VM.MARIST DOT EDU
                      E.ID.US>                 cc:
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                      Dist Stor
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                      03/06/2003 01:53
                      PM
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>I do not understand how you can get 50 clients on 1 disk pool to go to 20
>tapes.

Bill,

If I am wrong, someone will surely correct me, but what I think happens is
that when migrating the 50 clients from disk to tape, TSM will try to put
each one on its own tape (as collocate says it should).  So the first 20
clients each go to their own tape.  Then, when client 21's turn comes
around, TSM searches for a new scratch tape to hold this client.  If one
does not exist (because of MAX SCRATCH or simply out of scratch in the
library) TSM will go back and re-use the least consumed tape in that pool
for client 21 and migrates 21's data to that tape. Meaning that tape now
holds 2 clients.  Then for Client 22, the same thing happens:  it searches
for a scratch, when none are found, it finds the next least consumed tape
in
the storage pool and uses it.  And so on...

>I would think that 50 clients on 1 (collocated) disk pool will
>take 50 tapes.

The Disk pool would not be collocated (because it would normally be a
random
access pool, not sequential).  But, in our example, the destination tape
storage pool would be.

Hope that helps a bit!

Chris Murphy
IT Network Analyst
Idaho Dept. of Lands
Office: (208) 334-0293
cmurphy AT idl.state.id DOT us