To expand on Daniel's answer, you would want each RANK to be written to by only one concurrent i/o thread. So, if several LUNs are on the same rank, you might want to LVM them into a large volume, then define it to TSM. Otherwise, if 2 LUNs are on the same rank, then when TSM is writing to both volumes, you'll still get head contention. How much that'll actually impact you, well, that's up in the air also. You may want to test.
Also, I'm not so sure JFS is the best way to go. As near as I can tell, it's a 6-or-half-dozen issue. Personal preference seems to be the major differentiation. I've seen people claim that JFS is faster, I've seen people claim RAW is faster, so I'd say it's pretty much up to you. You may want to test both in your environment. Alex Paschal Freightliner, LLC (503) 745-6850 phone/vmail -----Original Message----- From: Daniel Sparrman [mailto:[EMAIL PROTECTED] Sent: Thursday, March 27, 2003 1:25 AM To: [EMAIL PROTECTED] Subject: Re: Defining TSM Disk pools on ESS wisdom wanted Hi I would suggest having as much volumes as possible. This is because AIX treats every volume as a PV, and one PV can only do one write or read at a time. So, using 24GB volumes is probably the best way to go. Also, JFS formatted volumes is the way to go. Best Regards Daniel Sparrman ----------------------------------- Daniel Sparrman Exist i Stockholm AB Propellerv�gen 6B 183 62 T�BY V�xel: 08 - 754 98 00 Mobil: 070 - 399 27 51 "Anthonijsz, Marcel M SITI-ITDGE13" <[EMAIL PROTECTED]> Sent by: "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]> 2003-03-27 10:18 Please respond to "ADSM: Dist Stor Manager" To: [EMAIL PROTECTED] cc: Subject: Defining TSM Disk pools on ESS wisdom wanted Hi, We are redefining our TSM disk pools on IBM ESS storage. We got 39 x 24 GB LUNs from our storage collegues. Total 936GB. LUNs are spread across the whole ESS. Now what is the best way, TSM wise and performance wise to define these disks to TSM? Make the volumes as large as possible? or define a volume per LUN, so I get 39 volumes of each 24GB? Use raw volumes or JFS formatted? Almost forgot: we're running TSM 4.2.1.9 on AIX 4.3.3 ML10 (yes I do know....All going out of support soon). ESS is FC connected. Thanks all for your eternal wisdom, Marcel Anthonijsz Central Data Storage Manager (a.k.a. storman) Shell Information Technology International B.V. PO Box 1027, 2260 BA Leidschendam, The Netherlands Tel: +31-70 303 4984 Mob: +31-6 24 23 6522 Email: Marcel.Anthonijsz.at.shell.com
