[SOLVED] Re: rsync 3.2.3 possible bug on md5sum

Alessandro Baggi alessandro.baggi at gmail.com
Fri Oct 29 09:52:41 UTC 2021

On 29/10/21 11:07, Alessandro Baggi wrote:
> Hi,
> I'm using rsync in a script to perform backups (using hardlink). It 
> works very well. In my case I use an alternative output format to 
> retrieve md5hash for every synced file so that I can save the hash and 
> run an integrity check when needed. I use this because I noticed that 
> the md5sum printed from rsync is like file md5sum and this avoid me to 
> calculate md5 checksum for every downloaded file and I can save time 
> (specially in the first backup on large dataset). Currently I use this 
> command:
> rsyc -avElHA --out-format"%i||%n||%C" source dest
> (well, I have reduced the original command to this to see if the 
> problem was generated by an option. The original command include ssh 
> option and timeout and other option)
> The problem:
> I noticed that using rsync 3.2.3 (protocol version 31) the md5 hash 
> does not correspond to the md5 file hash so if I run a check I got 
> corrupted file alerts.
> My current backup machine runs Debian 11.1 with rsync 3.2.3 (installed 
> from debian repository) and it works in pull. The following rsync 
> version is related to remote host.
> What I tested (I tested only trasferring one file of ~30MB with the 
> previous command):
> Sync from Debian 11.1 | problem found | rsync 3.2.3
> Sync from RockyLinux 8.4 | problem not found | rsync 3.1.3
> Sync from Debian 10.11 | problem not found | rsync 3.1.3
> Sync from Slackware15 (current) | problem found | rsync 3.2.3
> Sync file locally | problem found | rsync 3.2.3
> So this happens only when the remote host has rsync 3.2.3 while with 
> rsync 3.1.3 no problem.
> I don't know if this is a bug or a new behaviour of the protocol.
> Any help will be appreciated.
> Thank you in advance.
> Alessandro.

This is not a BUG. I read the manual page and found --checksum-choice 
option. Setting this to md5 will solve the problem.

Thank you for your time.

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