rsync --link-dest and --files-from lead by a "change list" from some file system audit tool (Was: Re: cut-off time for rsync ?)

Paul Slootman paul+rsync at
Tue Jul 14 06:59:25 UTC 2015

On Mon 13 Jul 2015, Andrew Gideon wrote:
> On the other hand, I do confess that I am sometimes miffed at the waste 
> involved in a small change to a very large file.  Rsync is smart about 
> moving minimal data, but it still stores an entire new copy of the file.
> What's needed is a file system that can do what hard links do, but at the 
> file page level.  I imagine that this would work using the same Copy On 
> Write logic used in managing memory pages after a fork().

btrfs has support for this: you make a backup, then create a btrfs
snapshot of the filesystem (or directory), then the next time you make a
new backup with rsync, use --inplace so that just changed parts of the
file are written to the same blocks and btrfs will take care of the
copy-on-write part.


More information about the rsync mailing list