When you migrate a file to Tivoli® Storage Manager storage, a stub file is created on the local file system. A stub file contains information that is necessary to locate and recall a migrated file.
A stub file can contain leading bytes of data from the original file called leader data. You can read leader data without triggering a file recall.
More leader data requires more space on your local file system. More leader data can be useful if you frequently run programs that read only the information at the beginning of files.
For Tivoli Storage Manager for Space Management clients on AIX® Enhanced Journaled Files Systems (JFS2), you can specify a multiple of the file system fragment size. The default value is the file system fragment size.
For Tivoli Storage Manager for Space Management clients on AIX GPFS™ and Linux x86_64 GPFS file systems, you can specify 0 or a multiple of the file system block size. The default value is 0.
For all file system types, the maximum value for a stub file size is 1 GB.