>> I'm backing up numerous large files on another machine on my local >> network. I've only been using rsync, but it occured to me that I >> might be able to save some time and space if I incorporate tar and >> bzip2. How will rsync interact with those? If I turn the whole >> backup into a big tar.bz2, would rsync need to redownload the whole >> thing if I change one file? If so, maybe I should turn different >> groups of files into tar.bz2 archives so rsync only needs to >> redownload an archive if one of its files has changed? > > It's not a default behavior, but there is an '--inplace' option. > > Also,there is a '--compress' option, if the bandwith is the only > problem, otherwise you can use lzma (with normal-best ratio) to either > acheive much better compression than bzip2 or still slightly better > ratio with improved speed / less cpu time with 'lzma -1' (fast mode). > > And if you're going to put a lot of files (like whole fs) into a > single tar just to transfer it to some remote destination, prehaps you > shouldn't be using rsync at all, since you'll end up reading all the > files anyway to create the tar. > Alternatively, you can save disk space on the source machine by piping > tar directly to destination, with compression either on the source to > lessen the banwidth, or on the remote to lessen the load on the source > machine cpu. > > That said, you can also use tar to create (or pipe) incremental backups > - just the changes since the time last one was made. Tar can handle that > as easily as rsync does, since it checks what needs to be transferred > each time anyway. > > -- > Mike Kazantsev // fraggod.net
Good stuff, thanks a lot Mike. - Grant
