Hi all - I have a file that is in excess of 400G.  Its actually a compressed directory of files.  When I try to upload it with s3tools sync, I get the error:

somefile.tar.gz -> s3://data/somefile.tar.gz  [part 10001 of 24481, 15MB]
 15728640 of 15728640   100% in    1s    14.93 MB/s  done
ERROR: Upload of 'somefile.tar.gz' part 10001 failed. Aborting multipart upload.
ERROR: S3 error: 400 (InvalidArgument): Part number must be an integer between 1 and 10000, inclusive

It looks like the # of parts has to be less then 10,000.  Why is this?