Re: Setting up DIRMC seq pool on disk

Richard,

I use a similar setup on TSM 4.1.5.0 on AIX 4.3.3.

I have a directory pool called "folderdisk" that is comrised of FILE
volumes sized at 40 MB each and spread across six physical disk drives.
Size is 2 GB but can be made much larger if necessary.  System has about
120 clients.  All DIRMC management classes are set for unlimited versions.
 Since I implemented that configuration in April, my system has sent
approximately 1.1 million directories to that pool totalling about 1.25
GB.

I've set my directory pool to migrate to tape at 99% full and continue
until empty.  So far that hasn't happened, but if it did it means that all
directories in the pool would be held on 1-2 physical tapes since the
destination tape pool is not collocated.  The 99% setting sounds risky
until you consider that 1% of 2 GB is 20 MB, and at an average of 1KB per
directory, migration would commence when that pool's capacity dropped to
less than 20,000 new directories.

My daily system maintenance backs up new directories from that sequential
pool to our copypool.  By having directories on FILE volumes, offsite tape
reclamation isn't affected except by how fast the database can look up and
update entries.  It made about 1000:1 improvement in performance over
having those directories on DISK volumes.

Answers to your questions:

1. You can send directories straight to the sequential disk.  That's what
we do.  Sessions and processes lock volumes so "some" smaller volumes are
arguably better than one big one.

2. Yes. You get to waste disk space - could be useful if angling for a
server upgrade.

Good luck.

Tab Trepagnier
TSM Administrator
Laitram Corporation








Richard Foster <Richard.Foster AT HYDRO DOT COM>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
12/14/2002 05:46 AM
Please respond to "ADSM: Dist Stor Manager"


        To:     ADSM-L AT VM.MARIST DOT EDU
        cc:
        Subject:        Setting up DIRMC seq pool on disk


Hi

I'm looking at setting up the famous DIRMC trick, with a primary
sequential
pool on disk. I have a couple of questions:

1) Is it a requirement to have the recommended setup
  DIRPOOL primary DISK: NEXTPOOL->DIRFILE
  DIRFILE primary SEQUENTIAL on DISK
or can we have our DIRMC point straight to the
  DIRFILE primary SEQUENTIAL on DISK?

If it's not actually requred, are there nevertheless any benefits from
having 2 pools?

2) Our current setup is
  DIRPOOL primary DISK: NEXTPOOL->DIRFILE
  TAPEPOOL primary SEQUENTIAL on TAPE
Unfortunately we share the TAPEPOOL with real files, and some of the
directory information has been migrated into TAPEPOOL.

Can anyone think of a way of retrieving just the directories from the
TAPEPOOL into the DIRPOOL/DIRFILE pools when it's set up?

One hope that struck me is that if we do a MOVE DATA on volumes in
TAPEPOOL
to other volumes in TAPEPOOL, will the DIRMC info be taken into account
and
directories automagically moved back into DIRPOOL/DIRFILE pools, or am I
too optimistic?


Our server is TSM 4.2.2.7 on AIX 4.3.3, but if there are any applicable
features newly available in TSM v5 I'd be interested, as we're planning to
upgrade.

Richard Foster
Norsk Hydro