If I use tapers compression, is it a bad idea to use the compression with zftape, or would it be better to not use tapers compression, and let zftape do it?
It is not bad as such to compress data twice (which would be the case when using tapers compression together with zftape’s compression) but it doesn’t make any sense. You won’t gain much further compression, but only waste CPU cycles. Tapers compression should be quite safe, as taper compresses single files; in contrast to tar -czf … which makes the entire data stream a large compressed block of data, which is really a bad thing with serious backups as a single bad byte at the beginning of the archive can make the entire archive unusable, well, it will be at least quite difficult to recover.
