What Performance Tuning Manual are you refering too? I am not sure of the maximum number of volumes but you SHOULD define more than one volume for the database, and put these volumes on separate disks because it allows simultaneous access to different parts of the database. Also, if you want to really use disk space efficiently, allocate a few large disk volumes rather than many small disk volumes. You can avoid losing space to the overhead processing that TSM does.
Regards, Demetrius -----Original Message----- From: Wholey, Joseph (TGA\MLOL) [mailto:[EMAIL PROTECTED]] Sent: Friday, January 25, 2002 1:20 PM To: [EMAIL PROTECTED] Subject: Re: Database Specs I agree, and I will do that... and thanks for the info... but why does my performance and tuning manual say not to span more than 12 volumes? -----Original Message----- From: William F. Colwell [mailto:[EMAIL PROTECTED]] Sent: Friday, January 25, 2002 2:13 PM To: [EMAIL PROTECTED] Subject: Re: Database Specs Joe - the number of volumes isn't the problem. You need to increase the bufpoolsize in the server dsm.opt file. Here is a 'q db f=d' from my system. The bufpoolsize parameter becomes the 'buffer pool pages' value in the q db. Bill Colwell - - - tsm: NEW_ADSM_SERVER_ON_PORT_1600>q db f=d Available Space (MB): 166,860 Assigned Capacity (MB): 166,860 Maximum Extension (MB): 0 Maximum Reduction (MB): 18,640 Page Size (bytes): 4,096 Total Usable Pages: 42,716,160 Used Pages: 37,947,974 Pct Util: 88.8 Max. Pct Util: 88.8 Physical Volumes: 45 Buffer Pool Pages: 65,536 Total Buffer Requests: 194,057,057 Cache Hit Pct.: 98.44 Cache Wait Pct.: 0.00 Backup in Progress?: No Type of Backup In Progress: Incrementals Since Last Full: 5 Changed Since Last Backup (MB): 1,542.07 Percentage Changed: 1.04 Last Complete Backup Date/Time: 01/24/2002 15:49:51 - - - At 12:54 PM 1/25/2002 -0500, you wrote: >I'm running TSM v 4.1.3 on System\390. My database is 47G and spread across 25 physical volumes (gets a 78% cache hit / not so great). > >One of my performance and tuning books recommends not spreading your database over more than 12 physical volumes. Could anyone explain why? What kind of performance/utilazation "hit" am I going to >incur by having my db spread across 25 volumes? > >Regards, >Joe Wholey >TGA Distributed Data Services >Merrill Lynch >Phone: 212-647-3018 >Page: 888-637-7450 >E-mail: [EMAIL PROTECTED] ---------- Bill Colwell C. S. Draper Lab Cambridge Ma.
