compress_dir
This parameter defines the directories where file compression occurs for backups on tape. Since file compression occurs on disk, you must provide enough space to compress the largest file in your database.
compress_dir = <dir>|(<dir_list>)
Default value: the directories specified in parameter backup_root_dir
If you want a parallel backup with software compression on local or remote tape devices, <n> copy processes are generally started in parallel, where <n> is normally the number of defined backup devices that are connected. To be able to use this parallel copy effectively also for the compression, define in directory compress_dir as many directories as there are copy processes. See also exec_parallel.
If you check the readability and completeness of the backup using -w|-verify, the files are restored back to the directories defined in compress_dir. To perform this process in parallel as effectively as possible, define as many directories as there are copy processes. The number of copy processes generally corresponds to the number of connected tape devices, see exec_parallel.