On Wed, Apr 22, 2015 at 10:17 AM, Kevin Korb <k...@sanitarium.net> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > No, even if bandwidth is your concern I would say that --checksum is > wrong. Maybe if bandwidth is so scarse that a few KB vs a few MB > equates to dollars then sure, use --checksum.
Yes, it does for me. This is especially when I update files whose size stays the same, and 'cause of the way transfers happened/failed, the destination time is later/equal to the source, then I needed to have the transfers forced, else rsync skipped over some. > Otherwise, letting > rsync re-delta-xfer everything is certainly faster and not much more > bandwidth intensive than --checksum. Plus that is only if you screwed > up and ran rsync wrongly in the past. This question shouldn't matter > as you should have synchronized mtime stamps so that rsync knows what > is going on. > > In my experience, --checksum is really only useful with > - --only-write-batch, or with --link-dest and known corruption, or with > - --itemize-changes and a watch for hardware induced corruption. > > If --checksum didn't checksum absolutely everything on both ends it > might be more useful. But apparently the use cases for --checksum are > so rare that nobody seems to care that --checksum is so stupid that it > checksums files that have different file sizes (and therefore could > only have a matching checksum if one file is a carefully crafted hash > collision) and it even checksums file that only exist on one (or the > other) end of the connection even though there is no file on the other > end to compare the checksum to. What a waste of time. > > On 04/22/2015 03:57 AM, Hendrik Visage wrote: >> On Wed, Apr 22, 2015 at 9:15 AM, Kevin Korb <k...@sanitarium.net> >> wrote: Normally, I would say that --checksum is actually slower >> than just letting rsync re-copy everything >> >>> Depends on the network capacity and costs associated with that >>> bandwidth :( >> >> and therefore is almost always the wrong thing to do. >> >>> Nope, not when you are bandwidth and budget constraint ;) >> >> However, in this case, you really don't want to overwrite the >> running OS even with files that are essentially the same. So, if >> the system is running from that storage then --checksum might >> actually be useful. >> >> On 04/22/2015 01:59 AM, Hendrik Visage wrote: >>>>> On Wed, Apr 22, 2015 at 1:03 AM, James Moe >>>>> <ji...@sohnen-moe.com> wrote: Hello, opensuse 13.2 linux >>>>> v3.16.7-7-desktop x86_64 rsync v3.1.1 >>>>> >>>>> I used rsync to copy /usr/ to another volume with these >>>>> options: --recursive --one-file-system --links --stats >>>>> --itemize-changes --quiet --delete --times After I had >>>>> modified the system to use the new /usr volume, I realized I >>>>> should have added: --perms --owner --group --executability >>>>> >>>>> So the target volume has everything set as "root root", and >>>>> useful bits like the SetUID mode are missing. >>>>> >>>>> Is there a way to use rsync to restore only the >>>>> permissions/owner/user and mode flags on the target volume >>>>> from the source volume? >>>>> >>>>>> *If* their sizes and times match, then I believe rsync does >>>>>> only the permissions/etc. changes with the -a option. >>>>>> However, I got into the tendency when doing these type of >>>>>> things, to use the -c/--checksum option, that way rsync >>>>>> makes sure the files haven't changed and will >>>>>> copy/update/etc. >>>>> >>>>> >>>>>> -- 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 > > - -- > ~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~ > Kevin Korb Phone: (407) 252-6853 > Systems Administrator Internet: > FutureQuest, Inc. ke...@futurequest.net (work) > Orlando, Florida k...@sanitarium.net (personal) > Web page: http://www.sanitarium.net/ > PGP public key available on web site. > ~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~'`^`'~*-,._.,-*~ > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v2 > > iEYEARECAAYFAlU3WSYACgkQVKC1jlbQAQfSxACg2q8IDYclf6XSKSX3VQF8s7LK > 7dgAn3Np86Q1vg+Q88oIY+ua/wEhHcXi > =wncA > -----END PGP SIGNATURE----- -- 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
