The idea of using --whole-file is that rsync behaves like tar and I thought
that I could set --whole-file so that the rsync method would behave like the
tar method and compare byte by byte rather than using checksums. I had a look
both in the rsyncp and BackupPC code (RsyncFileIO.pm). The use of checksums is
intrinsic in the way that the rsync transfer method works. So it uses the full
file MD4 checksums to determine whether a file has changed at all. Whether it
uses the whole file option for transferring changed files is unimportant since
99% of our files don't generally change between fulls. After poking around it
seems that the --whole-file option is specific to the actual rsync tool and the
BackupPC code along with RsyncP send a customized set of commands to the rsync
server. So it appears that not all of the rsync "program" options are
applicable. Maybe we already knew this but yeah this concludes my investigation
of --whole-file. I have attached a patch file that doesn't add the
--ignore-times argument to a full backup. It is based on backuppc 3.2.1.
-----Original Message-----
From: Les Mikesell [mailto:lesmikesell AT gmail DOT com]
Sent: Sunday, 29 September 2013 1:26 AM
To: General list for user discussion, questions and support
Subject: Re: [BackupPC-users] RsyncP and --whole-file
On Sat, Sep 28, 2013 at 7:30 AM, Till Hofmann <hofmanntill AT gmail DOT com>
wrote:
> Doesn't rsync calculate checksums even if you set --whole-file? It
> doesn't calculate block checksums but it still calculates file
> checksums - and if they match it skips the file (which only happens if
> you set --checksum-seed because otherwise it uses the current time as
> checksum-seed)
>
Yes, --whole-file still shouldn't send matching files. If you ran
over ssh you would be able to use ps to see what options were passed
on the remote command line. If you are poking around in the code,
maybe you could find a way to turn off the automatically added
--ignore-times that is added to full runs. That would make it go as
fast as incrementals, at the expense of a little safety.
--
Les Mikesell
lesmikesell AT gmail DOT com
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backuppc-ignore-times.patch
Description: backuppc-ignore-times.patch
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