The IBM® Tivoli® Storage Manager for Space Management client migrates files from your local file system to distributed storage and can then recall the files either automatically or selectively. Migrating files to storage frees space for new data on your local file system and takes advantage of lower-cost storage resources that are available in your network environment.
When a file is migrated from your local system to Tivoli Storage Manager storage, a placeholder, or stub file, is created in place of the original file. Stub files contain the necessary information to recall your migrated files and remain on your local file system so that the files appear to reside locally. This process contrasts with archiving, where you usually delete files from your local file system after archiving them.
The Tivoli Storage Manager for Space Management client provides space management services for locally mounted file systems, and it migrates regular files only. It does not migrate character special files, block special files, named pipe files, or directories.
File migration, unlike file backup, does not protect against accidental file deletion, file corruption, or disk failure. Continue to back up your files regardless of whether they reside on your local file system or are migrated to Tivoli Storage Manager storage. The IBM Tivoli Storage Manager backup-archive client is used to back up and restore migrated files in the same manner as you would back up and restore files that reside on your local file system. If you accidentally delete stub files from your local file system, or if you lose your local file system, you can restore the stub files or the complete files.
For planned processes, such as storing a large group of files in storage and returning them to your local file system for processing, use the archive and retrieve processes. The backup-archive client is used to archive and retrieve copies of migrated files in the same manner as you would archive and retrieve copies of files that reside on your local file system.
The Tivoli Storage Manager for Space Management client functions for threshold migration, demand migration, selective migration, selective and transparent recall includes processing GPFS™ file systems containing multiple space-managed storage pools.
The Tivoli Storage Manager for Space Management client has both a graphical user interface (the Tivoli Storage Manager for Space Management client GUI) and commands you can run from a shell. You can also use the commands in scripts and cron jobs.
For example, the following commands migrate all files owned by user ibm:
find /hsmmanagedfilesystem -user ibm -print > /tmp/filelist
dsmmigrate -filelist=/tmp/filelistYour Tivoli Storage Manager administrator associates management classes with your files. You, as a root user, can do the following:
- Select space management options and settings.
- Assign management classes to your files.
- Exclude files from space management.
- Schedule space management services.
The options and settings you define for the Tivoli Storage Manager for Space Management client determine which files are eligible for automatic migration, the order in which files are migrated, where the migrated files are stored, and how much free space is maintained on your local file system. You prioritize files for migration by their file size or by the number of days since your files were last accessed.