#1149604 rsync 3.5.0 much slower than 3.4 and consumes tons of CPU when tranferring very large files

Package:
rsync
Source:
rsync
Description:
fast, versatile, remote (and local) file-copying tool
Submitter:
Dianne Skoll
Date:
2026-10-01 20:09:01 UTC
Severity:
normal
Tags:
#1149604#5
Date:
2026-10-01 13:45:29 UTC
From:
To:
Dear Maintainer,

Ever since upgrading to rsync 3.5.0, my backups take much, much
longer and consume a lot more CPU time, with the fans on my PC
spinning up during the transfer.

Most problematic seem to be large (32GB) SD card images.  These
are backups of some Raspberry PI images; they are large sparse
files (so they read with many consecutive zeros) and I use the
--sparse option

The specific rsync options are:

rsync --one-file-system --sparse --delete --archive --verbose --progress --compress --compress-level=9 /dir/ host:/dir/

I'm not really sure how to make a reproducible test case for this.

Regards,

Dianne.
#1149604#10
Date:
2026-10-01 14:38:11 UTC
From:
To:
FYI, created an issue with upstream:

https://github.com/RsyncProject/rsync/issues/1115

Regards,

Dianne.