ADSM-L

Re: TSM Server Hosting - dedicated vs. shared

2006-03-13 18:20:07
Subject: Re: TSM Server Hosting - dedicated vs. shared
From: Remco Post <r.post AT SARA DOT NL>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Tue, 14 Mar 2006 00:19:46 +0100
Robin Sharpe wrote:

> Dear colleagues,
>
> It's time for us to split our TSM into several new instances because
> our database is now just too large -- 509GB -- and still growing.  My

wow... you do know that 560 GB is the limit (iirc?).

> initial plan is to create five TSMs - four plus a library manager -
> on the existing server (an 8-way, 12GB HP rp7410 with 15 PCI slots).
> This is cost effective since no additional hardware or license is
> needed - just lots of SAN disk for the databases, which we have
> available.  But, I've been thinking.... what do you think about the
> following:
>
> A more "creative" approach is to place the "new" TSM servers on
> existing large clients.  This has several advantages: -
> eliminates need to acquire new servers, saving physical room, power
> and cooling requirements, additional maintenance.

these could be accomplished by running multiple instances on one
dedicated server as well. The latter also saves the cost of upgrading
several tsm instances on multiple systems.

> -     client benefits by sending its backup to local disk using
> shared memory protocol. Eliminates potential network bottleneck.

good point. But you need to get the exact same amount of bits out of
your server, either via LAN or SAN. Lan adapters are cheaper and most
vendors recommend against mixing tape and disk access on one FC HBA. So
either way you'll probably want to increase the number of I/O adapters.
I'd go for the cheaper option....

> -     Client sends data to tapes using library sharing; no need for
> storage agent.

> -     Use of local disk eliminates the need for SANergy

or IBM SANfs or whatever. SANergy is dead anyway ;-)

> -     heavy clients "pay" for their usage by providing backup
> services for smaller clients.

... why not just charge them directly?

>
> There are also some concerns (not necessarily disadvantages): -
> May require CPU, memory, and/or I/O upgrades (still cheaper than
> buying a server) -     TSM operation may impact client's primary app.
> Can be controlled by PRM on HP-UX.

Still, I wouldn't want a big application running on my TSM server, so
probably, your colleagues don't want tsm on their machines either....

> -     Incurs licensing cost.
>

that, is a major point. If I was running eg. an oracle server I wouldn't
want to pay the oracle license for the extra cpu's required for TSM, and
vv. So having dedicated servers for an environment seems to be a very
good idea, mixing two (or more) applications on one server isn't (imnsho)

> Thanks for any insights.... Robin Sharpe Berlex Labs

I think that in the end you'll find the tco of a big tsm server with
multiple instances cheaper that of multiple instances all over the place.


--
Met vriendelijke groeten,

Remco Post

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