Re: Slow large file copy

Hi Danti,

away from my computer now, so I cannot check, but I suspect the --inplace to be the culprit. If rsync has to overwrite the file while transferring, it may not be able to check blocks in the original?

Regards
Hardy

-- 
I'm so stupid today, I could rule America.

On 29.07.25 12:55, Gionatan Danti via rsync wrote:
> Hi all,
> rsync seems slow to copy large files. The issue is not related to the transfer itself, which is quite fast, but to the discovery of different blocks.
> 
> For example, transferring a big (multi-GB) file from src (remote) to dst (local) with "--inplace" (to avoid a whole-file copy on dst) shows the following:
> 
> - if dst does not have a local file, or if -W was given, the copy immediately starts (but it clearly needs to transfer all blocks);
> 
> - if dst has a previous file version (and -W was not given), first dst reads the entire file, then src does the same, next different blocks are copied and finally dst re-read the entire file.
> 
> As dst and src file scans do not happen concurrently, and including the last whole-file read by dst, copy time is vastly increased at about 3x compared to an optimized process (with concurrent scans and without the final read).
> 
> Am I missing something? Can rsync be faster for large-file copies?
> 
> Regards.
> 


-- 
Please use reply-all for most replies to avoid omitting the mailing list.
To unsubscribe or change options: https://lists.samba.org/mailman/listinfo/rsync
Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html