From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]On Behalf Of
GUILLAUMONT Etienne
> I hope you will excuse me to be so direct but I think that you last answer
> is stupid,

Actually, I won't excuse you, and there's no need to be insulting.

> did you ever look at the price of a single drive library
> compared to a three drive library ?

Indeed I have. I install and configure them for a living.

> 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 guess it all comes down to what's more important--the cost of a proper
library vs. the ability to dependably make multiple backups of your valuable
data.

> 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.

You buy a smaller, scaled-down library. I stated earlier that single-drive
libraries were pretty much worthless. I should have said that they "were
pretty much worthless when used with TSM".

> 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 don't ever recall anyone on this mailing list claiming that TSM is only
for big companies. Is TSM expensive? Yes. But if I want to run a high-end
computer game, I don't go out a buy a cheap video card, either.

> 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)

Indeed it has.

> 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.

And just how do you propose to use a single drive to run space reclamation
on copy pool tapes? (This was the original question for this thread.) Copy
pool reclamation uses files from the primary tape pool, and you just can't
access two tapes at a time with one drive. If you're going to use a single
drive, you're either going to have to forgo copy pools, or live with the
fact that you can't run reclaims on them. (You can just delete copy pool
volumes; they'll just get recreated the next time you do a storage pool
backup.

> 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.

Let 'em laugh. If you can't afford a multi-drive library, you just can't
afford it. You're just not going to get to use TSM's full functionality.

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