It strongly depends on the bandwidth you have at disposal. For fast connections the compression can actually add overhead to the whole process, whereas for slow connections or if most of the available bandwidth is required by other critical processes the compression is strongly advised.
On the other hand there are some tricks you can adopt in order to limit the bandwith usage and/or speed up the syncronization. First of all, take in mind that rsync has a
--bwlimit option by which you can control the bandwidth usage. Then you can instruct ssh to spare some time, by using a quicker decipher algorithm, disabling x11 forwarding or disabling ssh compression (actually the last two are the default behaviour). For example:
Code:
rsync -az -e "ssh -x -c Arcfour -o Compression=no" source user@host:destination
Moreover you can determine the compression level in rsync by means of the
--compress-level option. Which combination of these conditions is the best for you, can be told only by testing. I'd say that
-z is generally a good option, but you must always take in account the balance between the usage of the local resources and the bandwidth usage in order to not interfere with other critical processes running on your server. Just my