On Tue, May 08, 2007 at 01:07:51PM +0200, Paul Slootman wrote: > On Tue 08 May 2007, Atte Peltomaki wrote: > > Source: > > > > md5sum: > > 2ac4a4ad88da17f49d26c9e578ce5432 somefile.exe > > sha1sum: > > eaabb30b716e993be000b89208e2d9f63e78f052 somefile.exe > > ls -l: > > -rwxrw---- 1 user group 109819105 Apr 2 10:48 somefile.exe* > > > > Destination: > > > > md5sum: > > 72c116866a75f859a19a150216768e52 somefile.exe > > sha1sum: > > 33b7d91fc6bd2a5bff292258c7d6eeb7db0aec8a somefile.exe > > ls -l: > > -rwxrw---- 1 user group 109819105 2007-04-02 10:48 somefile.exe* > > The files apparently both have the same size, timestamp, and other > attributes. Only the contents differ. > > You did not ask rsync to checksum the files... > > > What is the exact algorithm rsync uses to determien wether a file is up > > to date or not? > > Hmmm.... I thought this would have been in the manpage, but it's not > spelled out apparently. > Rsync by default compares size and mtime to determine whether a file > needs to be transferred. (I think the other attributes such as owner, > permissions are only updated, but don't necessarily incur a contents > sync, although I confess I'm not absolutely sure.) > > You need to supply the --checksum option if you want to make sure that > the contents are indeed identical. This is normally not done as that > would cause a massive IO load; cases that size and timestamp are > identical but not the contents don't usually happen...
The manual is indeed not very clear about the subject: """ The rsync remote-update protocol allows rsync to transfer just the dif- ferences between two sets of files across the network connection, using an efficient checksum-search algorithm described in the technical report that accompanies this package. """ Forgets to say that "efficient checksum-search algorithm" is not enabled by default *doh*. Anyway, thanks for help - using --checksum works, although it's quite slow. -- ____________ \ ______// Atte Peltomäki - [EMAIL PROTECTED] \ \\____ UNIX System Administrator - IT Server Team \ __// F-Secure Corp. PL 24, FIN-00181 Helsinki, Finland \ \\ Tel: +358 9 2520 0700, direct: +358 9 2520 5423 \ // http://www.f-secure.com \/ Integrated Solutions for Enterprise Security -- To unsubscribe or change options: https://lists.samba.org/mailman/listinfo/rsync Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html