Please don't use compression (-z) when rsyncing any zone files, whether the files are already compressed or not. Compression slows down the process since it uses significant CPU on both sides. And it certainly would not make sense to try to compress the already compressed files. There would be no significant file size savings, and the CPU usage would be significant.

For rsyncing the uncompressed files, the amount of data transferred is usually very small since only a few records change (if any) at any given time, so again compression just adds unnecessary overhead.

Therefore please don't use the rsync compression option.

Thank you,

Jeff C.