Split
A dump can be split into parts and written across multiple tapes. First, spanning must be enabled. Then you may specify the part size with the part_size parameter in the tapetype in amanda.conf(5), or with the tape_splitsize parameter in Amanda-3.1 and earlier.
Sometimes splitting requires caching, enabling Amanda to re-write a part that was not successfully written. This caching can be done in memory or on disk. In many cases, a cache is not required because the data is already available in holding disk. The part_cache_type, part_cache_dir, and part_cache_max_size tapetype parameters control this behavior.