The tape-to-tape operation that is adversely affected is reclamation. If the primay location of a file is in a random access disk pool, then TSM does not 'batch' the files together. Each transaction is a single file. The primary location can be a disk sequential access pool, but not random access. We originally came across this with DIRMC. We had the primary a DISK pool and then only created the copypool. The reclamation on the copypool tapes used to take days. Opened a PMR with Tivoli and got the 'working as designed' answer.
Bill Boyer DSS, Inc. -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED]]On Behalf Of Joe Pendergast Sent: Thursday, August 15, 2002 9:36 AM To: [EMAIL PROTECTED] Subject: Re: Bad performance from tape to tape Is the disk pool cached? I ran into a situation where the disk pool cache instead of tape was being used. This slowed my LTO drives to a crawl during certain operations. I now varyoff the disk pools before I run the process with expected results Don't forget to vary them back on at the end.. Note: the disk pool cache is a great help in restore time, but it can adversely the affect of what should be a tape to tape process. Halvorsen Geirr Gulbrand <[EMAIL PROTECTED]> on 08/15/2002 03:00:23 AM Please respond to "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] cc: (bcc: Joseph Pendergast/Corona/Watson) Subject: Bad performance from tape to tape Hi All, I have a performance problem when doing Space-Reclaamtion, or backup storage pool, when TSM is copying data from one tape drive to the other. Environment: Windows 2K server, TSM 4.2.1.15. Library, Compaq MSL5026, with 2 SDLT drives (Single Module Library). SCSI Controller, Compaq 64-bit/66Mhz Dual Channel Wide Ultra3 SCSI Adapter (Compaq version of Adaptec 39160) Moving data from Disk to Tape runs with expected speed (8-10 MB/s). >From Tape to tape speed is around 2MB/s. (50GB takes about 7-8hours.) Does anyone know why? It is killing my daily operations. Mvh Geirr G. Halvorsen TSM Enterprise Backup Specialist WMdata Danmark A/S