[CentOS] Need help to fix bug in rsync

Wed Mar 25 20:45:48 UTC 2020
Jon LaBadie <jcu at labadie.us>

On Wed, Mar 25, 2020 at 02:49:24PM +0100, Simon Matter via CentOS wrote:
> Hi,
> I've discovered a bug in rsync which leads to increased CPU usage and
> slower transfers in many situations.
> When syncing with compression (-z), certain file types should not be
> compressed during the transfer because they are already compressed. The
> file types which are not to be compressed can be seen in the man page
> section --skip-compress.
> Unfortunately skipping the default file types doesn't work and all
> transferred data is being compressed during the transfer. This is true for
> all versions since 3.1.0.
> Steps to Reproduce:
> 1. run 'rm -f Z ; rsync -azv alpha:z.gz Z'
> Actual results, transferred data was compressed during the transfer:
> sent 43 bytes  received 63,873 bytes  25,566.40 bytes/sec
> total size is 628,952  speedup is 9.84
> Expected results:
> No compression should happen for .gz file.
> Additional info:
> Note that the source file 'z.gz' was an ascii text file to show clearly
> that compression took place.

That may invalidate your testing.

rsync may not depend upon the filename extension
but instead check the magic numbers within the file
to determine whether to compress or not.

Jon H. LaBadie                 jon at jgcomp.com
 11226 South Shore Rd.          (703) 787-0688 (H)
 Reston, VA  20190              (703) 935-6720 (C)