Sparse files

Sparse files do not have disk space allocated for every block in the whole address space, leading to holes within the file. Holes are detected by their content, which is always zeros, and these zeros take up space.

The default is to restore the sparse file without the holes, which would leave more free disk space. The backup-archive client detects sparse files during a backup operation and marks them as sparse on the IBM Storage Protect server.

The backup-archive client backs up a sparse file as a regular file if client compression is off.