2. There definitely is a reason NOT to use RAID-5 for TSM. If you want your TSM server to snake like a worm put DB and Log on RAID-5, especially with a big stripe size - one of the best methods to shoot yourself in the leg. RAID-5 for diskpool volumes also will have performance impact but not so disastrous. It seems like you have enough disks to use mirroring or RAID-1 so why not. I still prefer to use raw LVs instead of filesystems despite the fact community on this list cannot completely agree is there any significant benefit or penalty for doing so. Using 'mklv -t tsm_db', '-t tsm_log' and '-t tsm_vol' fairly well describes what those LVs are for and I am not forced to exclude the files for the client on the server itself. IMO raw LVs are few percent faster than JFS files, there is no need to worry about large-enabled filesystems and file I/O buffering does not consume the memory TSM server can use better.
1. 8x 9GB after mirroring will give you 36 GB. It looks to be enough for both DB and Log. If your DB is not under 27 GB (cannot fit in three disks, you wrote <30) and you cannot afford 9-th and 10-th disk (DB and Log on separate disks gives best performance) you will be forced to use same disks for DB+Log. Create 1-1.5 GB LV in the center of each disk for Log. Create one or two LVs on the same disks for DB. It is recommended to mirror them through TSM but you can also use AIX mirroring or RAID-1. 3. For both DB and diskpool volumes it is better to have one (IMO) volume per disk. Other people on this list suggest more than one but opinions are consolidated that more than few will have negative impact on performance. Disk head moves will prevale disk reads/writes and performance will suffer. Zlatko Krastev IT Consultant "Varney, Patrick" <[EMAIL PROTECTED]> Sent by: "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]> 30.09.2002 22:21 Please respond to "ADSM: Dist Stor Manager" To: [EMAIL PROTECTED] cc: Subject: TSM Database Disk Layout Recommendations Hello All, I'm sure that this general question has been asked many times, but every situation is different. And I can't seem to get to the www.adsm.org site, so here goes. We just received some new SSA disks for our TSM servers and I'm looking for some advice on the best way to lay everything out. Here are the details on our planned environment (the SSA configuration has not been done yet, so it's flexible): Server: RS/6000 7026-H70 4-way processor 4GB memory 1 SSA HBA (2 loops) AIX 4.3.3 ML 10 TSM 4.2.2.12 Internal SCSI Storage: 4 x 9GB (current TSM database/log location) SSA Loop 1: 8 x 9GB RAID 5 Approx. 60GB SSA Loop 2: 8 x 72GB RAID 5 Approx. 500GB TSM Database: Less than 30GB TSM Log: 3-4GB Disk Storage Pools: 300GB My current plan is to put the TSM database on the 9GB SSA drives (using RAID 5, no TSM mirroring), the disk storage pool volumes on the 72GB SSA drives, and use the internal 9GB drives for database dumps to disk. However, I'm open to suggestion. Specifically, I am looking for answers to the following: - Where is the best place for the TSM database log volumes? And if they are sharing space on the SSA disks, is there any advantage to creating a separate file system (in general, is there any performance advantage/disadvantage to multiple file systems on one SSA RAID array)? - Is there any reason to NOT do RAID 5 on the SSA disks? - For the database and disk storage volumes, is it better to create more smaller (2GB) volumes or enable "large file" support and create fewer? Any help would be greatly appreciated. Thanks, Patrick Varney Pacific Gas & Electric Company Fairfield Information Operations Center (FFIOC) Enterprise Services Group (ESG), Senior Network Specialist * internal 8-227-2823 * external 707-436-2823 * pager 707-288-1513