Bonjour Etienne,

        Je viens de lire ton message sur la liste ADSM/TSM a propos de 
l'utilisation d'une unite de tape avec TSM.  Je n'ai pas tres bien compris 
ta solution au probleme.  Puisque je suis francophone (et que j'imagine 
que tu l'es egalement) je me demandais si tu pouvais me l'expliquer 
rapidement SVP?

Mon probleme est que sans deuxiememe unite de tape dans ma librarie je ne 
peus pas "reclamer" mes volumes de copypool.  Je peu faire un backup STG 
de mon diskpool sur un copypool, mais les tapes ne seront jamais 
"reclames".  Donc sa coute cher de tapes!!

Merci de ton aide,

Etienne Brodeur
ebrodeur AT serti DOT com
Serti Informatique Inc.
Anjou, QC
http://www.serti.com



I hope you will excuse me to be so direct but I think that you last answer
is stupid, did you ever look at the price of a single drive library
compared to a three drive library ? And I don't talk of the fact that most
3 drives libraries require the advanced library TSM feature which
multiplies the price of TSM by 4 ! But I think this is why you talk of a
BIG favour, it is because the price is BIG. If you compare the whole
solution, you will see that the whole solution has a price multiplied bye 
4
or more which makes it unaffordable for most companies.
I completely agree with you that a three drive (or at least two drives)
library is far more practical with TSM but it is very expensive. In
addition, what is the use of buying a 2 or 3 Tbytes library when you need
only 200 or 300 Gbytes.
I saw in this list some people saying that TSM is only for big companies
and that if you can't afford a 2 drives library, you should'nt buy TSM. I
also disagree with that, TSM has some functionalities which make it 
usefull
also for small companies (I had another storage software before and for
example, I saw that with TSM, I could reduce the number of tapes to buy,
and then to manage by 2 or 3)
I think it wouldn't be a lot of work for Tivoli just to add a few
functionnalities which would allow small companies to use it with a single
drive or with a small library. Don't forget that many companies uses only 
a
single drive on each server and if you talk to them of the price of TSM
with advanced library and a 3 drives library, they laugh.
Anyway, the cheapest configuration which I use without buying a "BIG"
library and which is practical with TSM is to add an external drive which 
I
use for the copy pool. You just need to have a drive which can contain at
least the amount of data you backup each day.
It is not a real problem that you have to change the copypool tapes each
day as it is what everybody make usually, even with a library. The only
thing which is a bit annoying is that I still didn't find a best way than
creating a script which set all the copypool tapes to writeonly except the
tape which is intended to be used. And I have to modify the script each
time I change a tape which is full. But I must admit I still didn't
understand very well how TSM manages the use of a single external drive.
Sometimes, I can put any tape and everything is ok, and some other times, 
I
put in an empty tape and TSM asks me for another. This is why I had to
create this script.
But I still didn't spend the time I should have to solve this problem.

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

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


  
                    Mark  
                    Stapleton            To:     ADSM-L AT VM.MARIST DOT EDU    
  
 
                    <stapleto@BER        cc:   
                    BEE.COM>             Subject:     Re: Off site copy 
with one drive??? 
                    Sent by:  
                    "ADSM: Dist  
                    Stor Manager"  
                    <ADSM-L AT VM DOT MA  
                    RIST.EDU>  
  
  
                    01/10/02  
                    13:19  
                    Please  
                    respond to  
                    "ADSM: Dist  
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From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]On Behalf Of
Etienne Brodeur
> Is it possible if I have a one drive library to use a copy storage pool
> for my backups?

Yes.

> I can backup to disk, then backup the diskpool to the copypool.  (this
way
> I should have all my data onsite and offsite).

Exactly. You backup from diskpool to offsite pool, and then you migrate
from
diskpool to primary tape pool.

> How do I then reclaim my copypool volumes?

You can't. TSM doesn't support a disk-based reclamation pool for
reclamation
of offsite tape pools.

> I can't reclaim to disk like I
> do with my onsite volumes for some reason (I don't see why not since the
> DB can track which file is on which onsite tape mount it and copy it to
my
> reclaimpool on disk.  Once that is done it can mount a scratch or
copypool
> volume and the offsite volumes would be reclaimed no?

One-drive libraries are pretty much worthless. Particularly if you have
large-capacity tape volumes, your disk-based reclamation pool needs to be
at
least 40% of the maximum size of the tape volume. In the case of LTO 
tapes,
that means 80GB of disk space for the reclamation pool.

Do yourself a BIG favor. Get a three-drive library.

--
Mark Stapleton (stapleton AT berbee DOT com)
Certified TSM consultant
Certified AIX system engineer
MCSE