Best format for backing up data in Blu Ray

"Tar really is the best format for archives. Every system you want to recover on will have it.

I use the tarfile Python module to make my tar.gz files and an index file with hashes. I have my program create a new tarball when the current one reaches a certain size. You could then run mkisofs and cdrecord with popen to create the ISOs and write them to disk.

I use tarsum.py to verify the hashes during recovery."