Hi, next step, According to https://rsync.samba.org/FAQ.html#13 "inflate (token) returned -5 This error means that rsync failed to handle an expected error from the compression code for a file that happened to be transferred with a block size of 32816 bytes. You can avoid this issue for the affected file by transferring it with a manually-set block size (e.g. --block-size=33000), or by upgrading the receiving side to rsync 3.0.7. "
Looks like rsync 3.0.7+ is not enough (currently using 3.1.1). New test with the backup of the day: Default blocksize 32816, read 7,657,969 bytes, failed inflate returned -3 (0 bytes) With --block-size=33000, read 7,690,797 bytes, failed inflate returned -3 (0 bytes) With --block-size=36000, read 8,018,923 bytes, failed inflate returned -3 (20 bytes) With --block-size=65536, success. So now we have an other workaround at least (instead of removing -z). I also have logs from rsync-debug on both sides (mentioned in https://rsync.samba.org/issues.html ), but it's huge (400 MB and 236 MB) and I'm not sure it's still useful with the two workarounds. -- Benoît Sibaud