Installation and User's Guide

vvvvconsulted to determine whether to back up, update, or expire each object. At thecompletion of the backup, the database file is deleted.Use the client option memoryefficientbackup yes. The average memory used bythe client then becomes 300 bytes times the number of directories plus 300 bytesper file in the directory being processed. Note that for file systems with largenumbers (millions) of directories, the client still might not be able to allocateenough memory to perform incremental backup with memoryefficientbackupyes.If the client option resourceutilization is set to a value greater than 4, and thereare multiple file systems being backed up, then reducing resourceutilization to 4or lower limits the process to incremental backup of a single file system at atime. This reduces the memory requirement. If backup of multiple file systems inparallel is required for performance reasons, and the combined memoryrequirements exceed the process limits, then multiple instances of the backupclient can be used to back up multiple file systems in parallel. For example, ifyou want to back up two file systems at the same time but their memoryrequirements exceed the limits of a single process, then start one instance of theclient to back up one of the file systems, and start a second instance of the clientto back up the other file system.Use the - incrbydate client option to perform an "incremental-by-date" backup.Use the Tivoli Storage Manager client exclude.dir option to prevent the clientfrom traversing and backing up directories that do not need to be backed up.v Reduce the number of files per file system by spreading the data across multiplefile systems.Related reference“Snapdiff” on page 464“Exclude options” on page 366“Incrbydate” on page 401“Memoryefficientbackup” on page 413“Resourceutilization” on page 444Performing a backup with limited bandwidthIf you plan to perform a backup over a network device that has limitedbandwidth, such as a modem, you can help reduce network traffic by usingadaptive subfile backup.An adaptive subfile backup sends only changed portions of a file to the serverduring successive backup operations.Perform the following steps to use adaptive subfile backup:1. Ensure that the server allows this type of backup. Check with your systemadministrator.2. Set the subfilebackup, subfilecachepath and subfilecachesize options in yourclient options file dsm.opt. If you set the subfilebackup option to yes and noexclude.subfile statements exist, Tivoli Storage Manager considers all files foradaptive subfile backup processing.3. Add an exclude.dir option to your client options file, which excludes thedirectory containing the subfile cache information.When you are ready to back up changes, adaptive subfile backup occurs as part ofincremental and selective backups.Chapter 4. Backing up your data 109