Dean, Long time no hear! At least by me!
Traditionally, based on information provided at an IBM conference a million years ago, we established that two volumes per physical drive is perhaps osmium. Actually, the number supposedly is between two and three. Something, as I recall, about getting sufficient TSM threads going to cause a disk queue length thus assuring the bottleneck is the I/O subsystem. One other thing to consider/try is file device class rather than disk device class. According to IBM, file device class is strategic, while disk device class is not. This COULD mean (note I said could) that DISK is going away sometime. I don't know about that, but file device class has lots of nice and unique features. You are in the perfect position to test some of this a report your findings! Try three disk device volumes and observer the throughput. Then try two, then try FILE, etc. I know, I know, if you had time to play you wouldn't be a TSM administrator! I've done some of this sort of testing (I'm not a TSM administrator so have plenty of time...) and have not seen a significant difference. One final thing: if I intend to migrate all of the data from the disk based pools daily, I would not use RAID5 for these volumes. I know that RAID5 does not perform well when you load it up with multiple simultaneous writes so be careful about that. Unless you have large writeback caches on your controllers... Kelly J. Lipp VP Manufacturing & CTO STORServer, Inc. 485-B Elkton Drive Colorado Springs, CO 80907 719-266-8777 [EMAIL PROTECTED] -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of Dean Winger Sent: Friday, February 02, 2007 1:02 PM To: [email protected] Subject: [ADSM-L] how many volumes per disk storagepool? Help Please It's been awhile since I have setup a TSM server for Windows (Tivoli Storage Manager Enterprise Addition 5.4). I am trying to find out what the optimum number of volumes I should define for each primary disk storage pool. I have a disk array that I broke into 3 Raid 5 groups; one group for Daily backups, one for SQL backups, and one for Archives. I also have a Raid 1 group defined for my DB backups and Log files. The Raid 5 groups consist of three 300GB SAS drives each. What size and how many volumes should I create for each Raid 5 group? For the DB and Log files I have a 270GB Raid 1 group. My database is currently around 40GB. What size should I make the DB and Log pools, and how many volumes should each have? Thanks so much Dean
