Re: What stripe size to use for TSM DB, LOG
Im my experience, it is better NOT to stripe the TSM database. Fragmentation is a way of life for the ITSM Database. This insures that I/O seek locations will be randomly spread across the entire database. If you stripe, you increase the number of heads that must move for each I/O operation. This hurts your potential multiprogramming level - better to have just one head move for each operation, freeing the other heads for use by other threads. So, don't stripe, unless you have the luxury of a completely idle system when you do DBBackup. On our system, everything happens all the time, and the best we can hope for is "somewhat less of everything else" during a DBBackup. The Log is VERY different; striping can help. The Log is run as a sequential, circular buffer. Roger Deschner University of Illinois at Chicago [EMAIL PROTECTED] On Wed, 2 Oct 2002, Seay, Paul wrote: >Stripe size is very hardware dependent. > >Paul D. Seay, Jr. >Technical Specialist >Naptheon Inc. >757-688-8180 > > >-Original Message- >From: Kilchenmann Timo [mailto:[EMAIL PROTECTED]] >Sent: Wednesday, October 02, 2002 11:25 AM >To: [EMAIL PROTECTED] >Subject: What stripe size to use for TSM DB, LOG > > >Dear all, > >>From a previous threat I learned, that TSM fills a DB volume an than goes to >the next one. Same is true for the LOG volumes - no "load balancing" like on >STG Volumes via client sessions. > >In this case (DB & LOG) I plan to use AIX LVM to stripe the logical volumes >over the available physical disks. The question here is what stripe size >should I use? Any suggestions? > >Many thanks in advance!!! > >Timo >
Re: What stripe size to use for TSM DB, LOG
Stripe size is very hardware dependent. Paul D. Seay, Jr. Technical Specialist Naptheon Inc. 757-688-8180 -Original Message- From: Kilchenmann Timo [mailto:[EMAIL PROTECTED]] Sent: Wednesday, October 02, 2002 11:25 AM To: [EMAIL PROTECTED] Subject: What stripe size to use for TSM DB, LOG Dear all, >From a previous threat I learned, that TSM fills a DB volume an than goes to the next one. Same is true for the LOG volumes - no "load balancing" like on STG Volumes via client sessions. In this case (DB & LOG) I plan to use AIX LVM to stripe the logical volumes over the available physical disks. The question here is what stripe size should I use? Any suggestions? Many thanks in advance!!! Timo
Re: What stripe size to use for TSM DB, LOG
I played with this at one time, with 6 36GB SSA disks. I found the smallest stripe size (4K) worked the best. I cut 50% of my DB backup time going from 128K to 4k stripe size. I saw little or no observable difference for my client backups, but that machine has other resource issues that may have masked the effect. Andy Carlson|\ _,,,---,,_ Senior Technical Specialist ZZZzz /,`.-'`'-. ;-;;,_ BJC Health Care|,4- ) )-,_. ,\ ( `'-' St. Louis, Missouri '---''(_/--' `-'\_) Cat Pics: http://andyc.dyndns.org/animal.html On Wed, 2 Oct 2002, Kilchenmann Timo wrote: > Dear all, > > >From a previous threat I learned, that TSM fills a DB volume an than goes > to the next one. Same is true for the LOG volumes - no "load balancing" > like on STG Volumes via client sessions. > > In this case (DB & LOG) I plan to use AIX LVM to stripe the logical volumes > over the available physical disks. The question here is what stripe size > should I use? Any suggestions? > > Many thanks in advance!!! > > Timo >
