rsync - Nov 2020 - Using --inplace and --sparse to a NetApp NAS through NFS

Hi.

I noticed, when using --inplace and --sparse to update a file of 36 G
located in an NFS mounted directory from a NetApp NAS through NFS, that
rsync is rewriting most of it: 27 G, while rsync (--stats) indicates a
literal data of only 262,144 bytes.

This do not happens with --inplace without --sparse: only ~204 K are
written, according to the size of a snapshot made before updating with
rsync.

Is it a known issue when combining --inplace and --sparse or is it due to
the file contents or NFS ?

Thanks.

I'm fine to do the initial copy with '--inplace --sparse' and the
subsequent incremental ones with only --inplace. The NAS will anyway
deduplicate zero-blocks after the copies.

Context:

  OS: Fedora-32 running kernel-5.7.8-200.fc32.x86_64
  NFS3
  rsync-3.2.3-1.fc32.x86_64

-- 
Francis