"It depends", on your environment. If you have REALLY big tapes, like LTO, so that all the data fits on one or two tapes, then you are going to have to collocate by filespace to get any benefit from multiple restores; otherwise multiple restores are all waiting on the same tape.
But we have a TSM server where we are using 20 GB tapes, and don't collocate by filespace. All the data for all filespaces are spread across the same say 10 different tapes. If I start a dsm (or dsmc) RESTORE for filespace /a, it mounts tape 1 and starts doing the restore. If I start a dsm (or dsmc) RESTORE for filespace /b at the same time, it waits on the first restore to get access to tape 1, so you get no benefit to start with. BUT, once the first restore dismounts tape 1 and mounts tape 2, the second restore can mount and start using tape 1 at the same time. So you will get parallel restores for about 80% of the time. Of course, that's up to the point that you max your network or host adapter throughput, or (in the case of Windows) the rate at which you can create files in the NTFS files system -- and assumes you have multiple tape drives free. Many ways to skin this cat. -----Original Message----- From: Conko, Steven [mailto:[EMAIL PROTECTED] Sent: Thursday, July 17, 2003 10:34 AM To: [EMAIL PROTECTED] Subject: Re: Multi session backup restore question We have a similar issue too. Is collocation of filespaces the only way (besides carving your system up in to multiple nodes) to acheive multiple restore sessions? Will it occur autmatically from a singe dsmc restore or do you need to manually invoke multiple sessions? Steve -----Original Message----- From: David Longo [mailto:[EMAIL PROTECTED] Sent: Thursday, July 17, 2003 10:25 AM To: [EMAIL PROTECTED] Subject: Re: Multi session backup restore question In order to have multi session "simultaneous" restore from tape pool then you must have this data in a pool that has collocation by filespace. If you have a big enough disk pool such that if you did a restore before migration had moved the data, then a multi session restore would use the disk pool and be multi session. David B. Longo System Administrator Health First, Inc. 3300 Fiske Blvd. Rockledge, FL 32955-4305 PH 321.434.5536 Pager 321.634.8230 Fax: 321.434.5509 [EMAIL PROTECTED] >>> [EMAIL PROTECTED] 07/17/03 09:48AM >>> Hello all, I am trying to work in a multi session backup and be able to use a multi session restore. What I have found is that with the maxresourceutilization set to 8 that my 350GB 8 processor AIX client is using only 4 data sessions and 4 control sessions. The data all goes to the disk pool and then the migration will use only 1 tape drive for this data. I then assume a multi session restore is not going to work. 1) how can I get this backup to use more sessions for data transfer? 2) Am I correct in believing that the multi-session restore is out because of the actions of the migration process? MUST this go direct to tape to have multi session backup and RESTORE? Thanks in advance, Matt ############################################################## This message is for the named person's use only. It may contain confidential, proprietary, or legally privileged information. No confidentiality or privilege is waived or lost by any mistransmission. If you receive this message in error, please immediately delete it and all copies of it from your system, destroy any hard copies of it, and notify the sender. You must not, directly or indirectly, use, disclose, distribute, print, or copy any part of this message if you are not the intended recipient. Health First reserves the right to monitor all e-mail communications through its networks. Any views or opinions expressed in this message are solely those of the individual sender, except (1) where the message states such views or opinions are on behalf of a particular entity; and (2) the sender is authorized by the entity to give such views or opinions. ##############################################################