An incremental backup backs up only new and changed files. The type of incremental backup depends on what objects you select to be backed up.
If you select entire file systems, the backup is a full incremental backup. If you select a directory tree or individual files, the backup is a partial incremental backup.
If you select entire drives, the backup is a full incremental backup. If you select a directory tree or individual files, the backup is a partial incremental backup.
The first time that you run a full incremental backup, Tivoli® Storage Manager backs up all the files and directories that you specify. The backup operation can take a long time if the number of files is large, or if one or more large files must be backed up. Subsequent full incremental backups only back up new and changed files. The backup server maintains current versions of your files without having to waste time or space by backing up files that exist in Tivoli Storage Manager server storage.
Depending on your storage management policies, the Tivoli Storage Manager server might keep more than one version of your files in storage. The most recently backed up files are active backup versions. Older copies of your backed up files are inactive versions. However, if you delete a file from your workstation, the next full incremental backup causes the active backup version of the file to become inactive. You can restore an inactive version of a file. The number of inactive versions that are maintained by the server and how long they are retained is governed by the management policies that are defined by your Tivoli Storage Manager server administrator. The active versions represent the files that existed on your file system at the time of the last backup.
To start a full or partial incremental backup by using the client GUI, select Backup, and then select the Incremental (complete) option. From the command line, use the incremental command and specify file systems, directory trees, or individual files to include in the backup.
During an incremental backup, the client queries the server or the journal database to determine the exact state of your files since the last incremental backup. The client uses this information for the following tasks:
Directories are counted in the number of objects that are backed up. To exclude directories and their contents from backup, use the exclude.dir option.
Consider an incremental command like dsmc incr c:\mydir\*.txt -subdir=yes. Assume that some files in c:\mydir\ do not have the txt file type. Rebinding and expiration occurs only for files that match the *.txt specification and whose directories still exist on the client file system.
You can use the preservelastaccessdate option to specify whether to modify the last access date after a backup or archive operation. By default, the access date changes after a backup or archive operation.