Installation and User's Guide

This option is valid only on the initial command line. It is not valid in interactivemode.Regulating backup and archive sessionsWhen you request a backup or archive, the client can use more than one session tothe server.The default is to use a maximum of two sessions; one to query the server and oneto send file data. The client can use only one server session if you specify aresourceutilization setting of 1.A client can use more than the default number of sessions when connecting to aserver that is Version 3.7 or higher. For example, resourceutilization=10 permits upto eight sessions with the server. Multiple sessions can be used for querying theserver and sending file data.Multiple query sessions are used when you specify multiple file specifications witha backup or archive command. For example, if you enter the following commandsand you specify resourceutilization=5, the client might start a second session toquery files on file space B.inc /Volumes/filespaceA /Volumes/filespaceBWhether or not the second session starts depends on how long it takes to querythe server about files backed up on file space A. The client might also try to readdata from the file system and send it to the server on multiple sessions.Note: During a backup operation, if you enter multiple file specifications, theresult might be that files from one file specification are stored on multiple tapesand interspersed with files from different file specifications. This can decreaserestore performance. Setting the collocatebyfilespec option to yes eliminatesinterspersing of files from different file specifications, by limiting the client to oneserver session per file specification. Therefore, if you store the data to tape, files foreach file specification are stored together on one tape (unless another tape isrequired for more capacity).Related reference“Collocatebyfilespec” on page 322Regulating restore sessionsWhen you request a restore, the default is to use a maximum of one session.Additional restore sessions are based on:v resourceutilization valuev how many tapes on which the requested data is storedv how many tape drives are availablev the maximum number of mount points allowed for the nodeNote:1. If all of the files are on disk, only one session is used. There is no multi-sessionfor a pure disk storage pool restore. However, if you are performing a restorein which the files reside on 4 tapes and some on disk, you could use up to 5sessions during the restore.2. The Tivoli Storage Manager server can set the maximum number of mountpoints a node can use on the server using the MAXNUMMP parameter. If theChapter 12. Processing options 445