Using the list archive, search on RAID or on my name. I've written about the perils of RAID 5 in a TSM environment a number of times. There is a white paper on our website that discusses SDLT vs. LTO tape performance and in there is a discussion about RAID5 as well. Something I learned during the performance testing.
Kelly J. Lipp STORServer, Inc. 485-B Elkton Drive Colorado Springs, CO 80907 [EMAIL PROTECTED] or [EMAIL PROTECTED] www.storsol.com or www.storserver.com (719)531-5926 Fax: (240)539-7175 -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED]]On Behalf Of PINNI, BALANAND (SBCSI) Sent: Tuesday, November 12, 2002 7:59 AM To: [EMAIL PROTECTED] Subject: Re: Raid 5 or 0? How about Raid0+1 . That is performance and availability. Balanand Pinni SBC Services Inc. Work:314-206-5911 Pager:1-800-451-6897 Email ID :[EMAIL PROTECTED] [EMAIL PROTECTED] e.mail pager -----Original Message----- From: Gianluca Perilli [mailto:[EMAIL PROTECTED]] Sent: Tuesday, November 12, 2002 4:44 AM To: [EMAIL PROTECTED] Subject: Re: Raid 5 or 0? Choosing RAID5 is a good solution if you have data heavily accessed in a read mode: in fact in this case you don't face the performance problem of the parity calculation/writing: for example choosing it for the TSM DB it is not a bad idea; furthermore RAID5 is more effective in the usage of the disk space. The RAID 0 is a good choice whenever you want high performances because you can leverage the data spreading on multiple disks and you don't have to calculate any parity: however if you have a problem on a disk you loose all your data because the system cannot re-build these data as no parity exists. Then, if you want good performances without incurring in problems of lost data, it is better to think about RAID10, ie a RAID0 mirrored to another RAID0 array: the performances and security are the highest, but unfortunately the disk space usage too. So RAID10 is a good choice for the heavily written data, like for example the Recovery log in TSM. Hope this helps. Cordiali saluti / Best regards Gianluca Perilli EMEA Support, GlobalResponseTeam Storage e-mail: [EMAIL PROTECTED] Tivoli Software, IBM Software Group Via Sciangai 53, Rome 00144 Italy Office : +39.06.59664581 Mobile: +39.335.7840985 Fax: +39.06.59662077 Luke Dahl <[EMAIL PROTECTED] To: [EMAIL PROTECTED] OV> cc: Sent by: "ADSM: Subject: Raid 5 or 0? Dist Stor Manager" <[EMAIL PROTECTED] .EDU> 11/11/2002 11:07 PM Please respond to "ADSM: Dist Stor Manager" Hi, We're considering changing from RAID5 to RAID0. Info: Solaris 5.8 TSM Server 4.2.1.15 Storage array 21 36Gb disks (currently RAID5. Is this a wise move? If we make the change, any recommendations on the stripe setting? Default is 64Kb, but it can be set while we configure... Performance seems quite slow with RAID5 and we have a development box we're going to throw this at. Any thoughts or recommendations are much appreciated. Luke Dahl NASA - Jet Propulsion Laboratory 818-354-7117
