LinuxQuestions.org - Rsync problem: command not found

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- - Rsync problem: command not found (https://www.linuxquestions.org/questions/linux-software-2/rsync-problem-command-not-found-658831/)

Instead of making a symlink (though it works), you can use the --rsync-path switch:

Code:

--rsync-path=PROGRAM specify the rsync to run on remote machine

Rsync is required on both ends

Working on a new mail server install, when I tried to copy the information from the old server using rsync via ssh I got the same error.

Installed rsync on new machine..... error went away. It makes sense that you need rsync on both based on the fact that it uses a specific algorithm to determine file changes.

Quote:

The rsync utility uses an algorithm invented by Australian computer programmer Andrew Tridgell for efficiently transmitting a structure (such as a file) across a communications link when the receiving computer already has a similar, but not identical, version of the same structure.

The recipient splits its copy of the file into chunks and computes two checksums for each chunk: the MD5 hash, and a weaker but easier to compute 'rolling checksum'.[18] It sends these checksums to the sender.

-- https://en.wikipedia.org/wiki/Rsync

There's a simple way to use rsync when it is only installed on one side - mount the other side's relevant file system as a file share (sshfs, or nfs, or samba, or whatever), and then use rsync to copy files to/from that file share.

I like using rsync in this fashion because the other side doesn't need any special setup other than serving up a file share.

The only real downside to having rsync only on one side is that you can't conserve bandwidth by doing binary checksum comparison. You have to rely entirely upon timestamp/filesize to detect unchanged files. IMHO, this is not a big deal. I mean, what are the chances that a file is going to have its timestamp altered but the contents remain the same?

Okay, depending on the file share and file system involved, this could happen a LOT. In particular, there are Windows issues with daylight savings time, and Windows file systems don't have the same timestamp granularity as *nix. You can work around the latter by using a slop range of a couple seconds, but daylight savings time is ... annoying.