Hi, On 03.08.19 18:59, Ted Toal wrote: > Ged, > >> BackupPC shines, I think, in less well-constrained situations. >> >> Given the boundaries I wonder if you wouldn't do better with something >> simple like a script which runs 'find' to find the files to be backed >> up, plain vanilla rsync to do the actual transfers, and de-duplication >> provided (if necessary) by one of several filesystems which offer it. > > We looked at a lot of different solutions, and BackupPC seemed best. I > really like it. I’m not sure that any script we set up could do any better > job finding the files to back up, than rsync via BackupPC with the > file-size-constraint option specified. If I understand it correctly, > incrementals DO NOT read the entire file contents and compute a checksum, but > work strictly off of file modification date, so finding the files requires > only reading the directories and not reading the files themselves, right?
Correct. FWIW, `find` with inspection of the modification date (-newer) calls getdents64 via readdir for listing directory entries directly, then lstat for each entry. `rsync` does exactly the same; so for the unchanged files, both should be identical. (In other words, I don't think that an additional mirroring script based on find buys you anything over BackupPC's rsync use.) What *might* be a problem: I remember the painful experience of listing directories with more than a couple files via NFS. [1] explains a possible reason: readdir is not exactly the most efficient way to get such lists, in particular if the latency to get another chunk of the directory listings is significant. But probably that won't matter if you have to call lstat per file anyways. [1]: http://be-n.com/spw/you-can-list-a-million-files-in-a-directory-but-not-with-ls.html Alex > _______________________________________________ > BackupPC-users mailing list > BackupPC-users@lists.sourceforge.net > List: https://lists.sourceforge.net/lists/listinfo/backuppc-users > Wiki: http://backuppc.wiki.sourceforge.net > Project: http://backuppc.sourceforge.net/ >
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