How can I minimise data transfer when rsyncing subsequent dumps?

[Steve Drangus]

What I'm trying to do is generate a full dump of my database using mysql shell, like so:

util.dumpSchemas(["my_db"], "outdir", {threads:5, bytesPerChunk: "256M"})

And then rsync it to a remote nfs share that contains a previous version of the dump. I'd like to minimise the transferred data, so I was hoping mysql shell's dump utility would generate file chunks for old unchanged data in a repeatable manner (i.e. the files would checksum the same). However this has proved not to be the case, and in fact virtually all the files checksum differently after minor table updates.

The mysql docs say that the primary key is used to order & chunk the data, so I optimistically thought that any tables with autoincrementing primary keys should dump in a deterministic way. But that appears not to be the case as the produced files don't checksum the same. Maybe it's ordering rows in reverse?

In any case I would love suggestions for how to do this.