1) Use the DSM accounting records to get the total amount of data backed
up per day.
Chart it. As that grows, you disk pool needs to grow.
2) The amount of data backed up per day, may not have much relation to
the amount of data you need to STORE.
Run SELECT on the OCCUPANCY table on a weekly basis, total up the amount
of TSM tape storage occupied.
These number are funky because most people use tape drive compression;
but you can still get a RELATIVE growth rate.
3) When planning on buying xxxGB of new tape storage, remember that your
tapes are NEVER 100% full.
If you think you need 2TB of tape storage, divide that by the GB per
cartridge, then divide by 2 to allow for compression, then divide by .65
to account for the unrecycled tapes, to arrive at how many tapes you
need.
4) From the SUMMARY table, you can SELECT on MOUNT activity and
calculate the TIMES that tapes were mounted in drives. Add them all up,
and you can see how many hours per day your tape drives are busy. I
doubt it would ever sum to 24 hours, due to a bit of wasted time on
mounts and dismounts. I don't have a fixed rule of thumb there, but if
you see the hours per day per drive going up, my guess is you shouldn't
plan on getting more than 18 hours per day, per drive.
Wanda Prather
"I/O, I/O, It's all about I/O" -(me)
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Jeff Kloek
Sent: Monday, March 21, 2005 12:24 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Capacity Planning
For the last few years, I was the point-man in the UNIX department at my
last job for Tivoli Storage Manager support. We had a separate
department
called Storage Management that contained the "Architects" of that
environment. During my time there, I got very interested in TSM and have
studied it a great deal.
Now I'm at a company who also uses TSM, but where there isn't an
architecture type of group, and we're running into growth related
issues.
I believe the end-run of a detailed study of TSM results in:
a) the ability to predict the impact of a specific client (or group of
clients) growth on the overall needs for that environment, and
b) the ability to predict the increased needs of storage pool disk and
tape mount requirements based on changes like that in item a) above.
Up to this point, I'm just not quite there. I've built some reports like
daily host backup amounts, daily changes in host occupancy; studied the
details of the policy domains, policy sets, management classes, and copy
groups, obtained a general understanding of the retention policies,
etc.,
but I still don't quite have my hands around the big picture.
Right now, we're in a situation where our daily backups are going to
disk
just fine. The problem we're having with the enormous increase in Email
backups (we don't currently delete anything due to a recent decree by
management) is that our offsite copy pool backups are no longer
completing
within the 24 hour magic window.
I suspect there is a set of procedures that is generally accepted that
would help to define increasing needs for the TSM environment. I'm sure
I
need to begin capturing the daily amounts of data that gets backed up in
the BACKUP STORAGE POOL processes, and perhaps even the MIGRATION
processes.
All that being said, is there a set of guidelines that can help me
define
exactly what increase in hardware we might need, or something that would
help me to tell management that "to add another X amount of drives would
get us back to completing the offsite copy pool process (and thus the
entire day's processing) to within the 24 hour window?
Details:
TSM Server 5.2.2.0 on AIX 5.2 7026/6H1; 4Gb memory; 3584 Library; 18
LTO2
drives. Currently there are no drives to spare to add additional mounts
for the Backup Storage Pool processes.
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