Well then, IBM needs to revisit their own technical documents. From a recent Technical Exchange series on TSM Performance Tuning:
OS Platform Specific Recommendations - UNIX Use raw logical volumes for best TSM server performance AIX: mklv -ae -t tsmdb -y db1 volgrp1 64 hdisk4 mklv -ae -t tsmlg -y lg1 volgrp1 64 hdisk5 TSM: define dbvol /dev/rdb1 define logvol /dev/rlg1 James Hunt <[EMAIL PROTECTED]> Sent by: "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]> 01/22/2004 03:01 PM Please respond to "ADSM: Dist Stor Manager" To: [EMAIL PROTECTED] cc: Subject: Re: RAW vs. JFS question There are not any performance improvements when the TSM Recovery Log or TSM Data Base is put on RAW volumes. It would be much easier to manage if the environment is all JFS. There may also be a need in the future to run multiple instances of the TSM server code on the same box. Which RAW could cause problems. Also there are some concerns when working with RAW volumes. Do not use AIX to mirror Raw Logical Volume with TSM. Instead use TSM mirroring facilities. AIX puts information in a control block on disk which will overwrite TSM's control information. Do not change the size of RLV's using SMIT. Please refer to 'TSM for AIX Administrators manual for EXTend DB and EXTend LOG commands. The TSM Administrator must be careful not to start multiple instances of TSM Server code which may use the same RLV's. With AIX there is no locking when using RLV. TSM attempts to fix this by implementing locks using files in the /tmp directory. These locks may be deleted if programs are run which clean up the files in the /tmp directory. Jim Hunt _______ GlassHouse Technologies, Inc. [EMAIL PROTECTED] -----Original Message----- From: Paul Zarnowski [mailto:[EMAIL PROTECTED] Sent: Thursday, January 22, 2004 1:36 PM To: [EMAIL PROTECTED] Subject: Re: RAW vs. JFS question At 06:24 PM 1/22/2004 +0100, you wrote: >On Thursday 22 January 2004 15:38, Bill Boyer wrote: > > The "new" TSM runing guide recommends using RAW volumes for performance > > reasons. I think IBM's recommendation is raw for DB and LOG, and JFS for stgpool volumes (because of potential readahead benefits in JFS). >And what about the DirectIO and AsyncIO? If you use DirectIO, don't you >bypass the file system cache? DirectIO is only usable on AIX for LVs under 2G. That's pretty restrictive. >Stef ..Paul -- Paul Zarnowski Ph: 607-255-4757 719 Rhodes Hall, Cornell University Fx: 607-255-8521 Ithaca, NY 14853-3801 Em: [EMAIL PROTECTED]