Backup and Migrate gives me a tar ball
This is not an issue with the module.

The most likely cause of the problem is that your local system is missing gzip, so the backup and migrate module is unable to turn the tar-file into a gzipped tar file.

The command to do that is not tar -cvzf (which you've tried), but gzip. I.e.:

gzip 127.0.1.1-2015-01-12T17-23-50.sitearchive.tar


This should produce a valid 127.0.1.1-2015-01-12T17-23-50.sitearchive.tar.gz, but if you try this on the local system, it will probably fail telling you that it can't locate gzip.

The best fix would be to install gzip on the local system.

Alternatively, you may export the file to some system that has gzip, and do the gizipping there.