--checksum is only slower than re-copying if your network connection between the hosts is similar in speed (or faster than) each host's local disk access.
If local disk access is 10x your network link, it is definitely not slower than re-copying. Having said that, it really is *very* slow, and before you use it you should have a clear situation in mind that makes it plausible that two files could have the same size and last mod time and still not have the same data. Or, alternately, be in a situation where a bit flip would be catastrophic. Such situations are not common. On Thu, Jul 14, 2022 at 04:26:48AM -0400, Kevin Korb via rsync wrote: > You should almost never use --checksum. It is slower than just re-copying > everything. You should almost always use --times (or --archive which > includes --times). Without this rsync is almost as dumb as cp. Also, ssh > has been the default --ssh for a long time. > > On 7/14/22 04:22, Fourhundred Thecat via rsync wrote: > > Hello, > > > > I want to sync local folder to remote server. When I run follwing > > command repeatedly, it always transfers everything each time again and > > again: > > > > rsync --rsh='ssh' foo/ server:/foo/ > > > > does it mean I have to always use either --checksum or --times, to > > prevent repeated transfer of files that have not changed ? > > > > thank you, > > > > -- > ~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._., > Kevin Korb Phone: (407) 252-6853 > Systems Administrator Internet: > FutureQuest, Inc. ke...@futurequest.net (work) > Orlando, Florida k...@sanitarium.net (personal) > Web page: https://sanitarium.net/ > PGP public key available on web site. > ~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._., > > -- > Please use reply-all for most replies to avoid omitting the mailing list. > To unsubscribe or change options: > https://lists.samba.org/mailman/listinfo/rsync > Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html -- Please use reply-all for most replies to avoid omitting the mailing list. To unsubscribe or change options: https://lists.samba.org/mailman/listinfo/rsync Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html