When archiving large amounts of encrypted data, you can compress the data, for example, to reduce the number of tape volumes needed.

Some tape devices make use of their own compression when you store data. Encrypted data is not highly compressible, so you might want to compress your data prior to encryption using the HWCOMPRESS keyword.

During DUMP processing, only user data may be compressed. This means that VTOC and VVDS tracks that are processed are not compressed. The data set names and other content from the VTOC will appear uncompressed in the output dump data set.