OK, I basically keep a diskpool big enough to contain an entire night's
backups.
Now this is compressed...
Things to remember:
Clients, even though using compression, allocate enough disk space
in the diskpool to hold the file uncompressed, once the transfer is
completed, unused space is freed. If you have a lot of concurrent sessions
sending large .dbf files (that compress nicely) you end up with sessions
rolling tape when they don't really need to because yadayadayada.... trust
me
When there is lots of client activity and you initiate migrations,
you have TSM DB lock contention with inbound sessions & the migration
processes, not as bad now as in the past but it is still there just the
same.
Another "trust me", in a limited number of tape drives environment
you don't want inbound sessions & migrations fighting over tape drives.
just things I've run into
later,
Dwight
-----Original Message-----
From: Gerard M Hanway [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, October 24, 2000 9:54 AM
To: [EMAIL PROTECTED]
Subject: Optimum diskpool size
I look after the companies TSM environment. Approx 700 servers back up an
average of 60-70gb per night. The ADSM server runs on OS/390 with 500 OS/2
and
200 NT clients. I have 2 primary disk pools, one of 45GB for the NT
servers(colocated) and one of 4GB for the OS/2 servers(non colocated). HIMIG
is
set to 80% on the large pool and usually results is migration starting
between 2
and 3am each morning and completing around 9am.
However the storage people have just been in touch wanting to know what I am
doing with so much disc in the large pool. Basically they want 30gb back
leaving
leaving me with just 15gb. I suspect that things should continue to work
just
with migration kicking it a lot earlier however I would welcome opinions.
Is there a recommended ratio of disk pool size to amount of data backed up.
What
ratio do most people use. Are there quantifable performance impacts in
running
migration at the same time as backups. I do know from experience that with
migration starting significantly earlier I can expect a lot of additional
tape
mounts. But it might be argued so what.
Are there any other gotcha's
Gerard
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This document is strictly confidential and is intended for use by
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Allied Irish Banks
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