Richard, We just heard from EMC that the "4 x n +1" optimization is a "myth"... being spread by their technical support staff, field service techs, and training instructors. Their engineers say that Clariion will provide optimum performance with any reasonable drive count.
We use RAID-3 on ATA for TSM disk pools, and RAID-5 on Fiber and ATA for general disk storage - like data drives of our Windows file servers. Tab Trepagnier TSM Administrator Laitram, L.L.C. Richard Rhodes <[EMAIL PROTECTED]> Sent by: "ADSM: Dist Stor Manager" <ADSM-L@VM.MARIST.EDU> 02/10/2006 06:21 AM Please respond to "ADSM: Dist Stor Manager" <ADSM-L@VM.MARIST.EDU> To ADSM-L@VM.MARIST.EDU cc Subject Re: Disk config question - Block size I would suggest you contact EMC. I believe they have information about setting up a clariion for TSM. A couple comments from things I've heard from EMC. . . . . EMC used RAID3 in their VTL, and is best for streaming when ATA drives are used, for up to about 10 concurrent read/write data streams. RAID5 is best for streaming with NON-ata drives. EMC has stated a bunch of times that you should not change the default 64k strip size without talking to EMC support (you indicated you weren't, so good). There are internal software design issues that make this optimal. rick Andy Huebner <[EMAIL PROTECTED] ONLABS.COM> To Sent by: "ADSM: ADSM-L@VM.MARIST.EDU Dist Stor cc Manager" <[EMAIL PROTECTED] Subject .EDU> Disk config question - Block size 02/09/2006 06:34 PM Please respond to "ADSM: Dist Stor Manager" <[EMAIL PROTECTED] .EDU> I am preparing a Clariion CX-300 for TSM disk pools. TSM will be the only system so I can tune it from end-to-end. There will be two 4+1 RAID5 groups holding the disk pools. RAID5 or RAID3 are the only choices due to the number of disks that were purchased and the amount of space that I need. The settings we are considering: Element size of 64k. This means a 256k write from TSM is one stripe. Cache block size of 16k. Larger I/Os for the disk pools larger cache blocks should work better. AIX Logical Volume block size of 64k. This will match the element size. Has anyone done this type of tuning and been able to test variations? Andy Huebner This e-mail (including any attachments) is confidential and may be legally privileged. If you are not an intended recipient or an authorized representative of an intended recipient, you are prohibited from using, copying or distributing the information in this e-mail or its attachments. If you have received this e-mail in error, please notify the sender immediately by return e-mail and delete all copies of this message and any attachments. Thank you. ----------------------------------------- The information contained in this message is intended only for the personal and confidential use of the recipient(s) named above. If the reader of this message is not the intended recipient or an agent responsible for delivering it to the intended recipient, you are hereby notified that you have received this document in error and that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this communication in error, please notify us immediately, and delete the original message.