Charles,

For years we operated TSM with very little disk space.

The trick is to use small disk pools of 5-10 GB with several volume files,
and set a fairly low migration threshold - say 10-20% or so.

In our case one of our disk pools was 4 GB as 20 x 200 MB volumes.  We ran
with HI=10, LO=0, so as soon as the clients committed 400 MB of data,
migration started and sent a pretty good chunk of data to tape.  We
migrated data to 3570XL media with an average I/O of 8 MB/s, so migration
took only about a minute or so.
Because our disk pool was so small we set a MaxSize of 1 GB (25% of the
disk pool) so anything bigger went straight to tape anyway.
All of our production libraries have four drives each so we had enough
mount points to accommodate both clients sending to tape and migrations.

Tab Trepagnier
TSM Administrator
Laitram LLC








"Bell, Charles (Chip)" <Chip.Bell AT BHSALA DOT COM>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
10/11/2005 01:06 PM
Please respond to
"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>


To
ADSM-L AT VM.MARIST DOT EDU
cc

Subject
Re: Fw: Configuring JBB






Not a dumb question at all. This shop is strapped for resources. We are
looking at getting a VTL in here, but in the interim, I have a 3584 to
deal with. We have 4 LTO1 and 4 LTO2 drives. We do not have enough disk
to send him there, and our admin sched has recently outgrown the
environment that was supporting, so a VTL will kill several birds. So to
answer the question more directly, we just do not have the disk (or
SANergy money) or space for FILE to put it. I am fully aware that going
to tape is not helping, but I don't have many options as far as
resources are concerned. Another thing of note is that I put this node
in its own domain with own mgmt class to separate it out from our main
domain for Wintel boxes. This was done because of the sheer data amount
that they expected this server to host in the next few years (multiple
TB's). Yikes! Since I have collocation turned off until the resource
situation improves. I simply did not want to mix this node with the
others. The node has thus far filled 40 LTO2 tapes and is constantly
growing.  :^(

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Allen S. Rout
Sent: Tuesday, October 11, 2005 12:49 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] Fw: Configuring JBB

==> On Tue, 11 Oct 2005 12:27:10 -0500, "Bell, Charles (Chip)"
<Chip.Bell AT BHSALA DOT COM> said:

> Already scheduled for it, and planning on posing my question there if
I
> don't have a solution in place by then. Thanks!

Might be a dumb question, but you mention

> The node in question is holding onto a tape drive for 20+ hours per
backup
> because of the file inspection it has to do, which is why I want to
get JBB
> to work.

I don't know why you've chosen to do this direct to tape; could you get
your
resources free by hitting a DISK or FILE devclass instead?

The use of a tape might be slowing down your backups, dramatically.
Especially with erratic streams, tape positioning time can come to
dominate
your backup.


- Allen S. Rout


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