Jamie - zxfer

I love the show and from it I discovered zxfer. Could Allan go into detail on how specifically the "grandfather" option works in zxfer?

On my source pool I have snapshots deleted after 30 days. But on the backup pool I'd like to keep the backups much longer.

I'm not sure I understand the explanation in the man page for zxfer. Do I set it as -g 365 if I want to keep the snapshots for a year on the backup pool?

Thanks for the great show guys!