It´s nice that he references to ZFS in his article, but i think his opinion stated in #”PostgreSQL to Scale to 1 Biilllliooonnnn Users, Dr Evil would be proud” is dangerous:
Backup is irrelevant for those of you who care about this discussion. LVM/ZFS snapshots are the rule of the land.
Well, when the first disaster hits your datacenter (and such disaster begin with a failed disk too much) , you will recognize that you are toast without tapes or at least with a disk-based backup on a different storage as a last line of defence. Neverever rely on a single pool of disk blocks on a single machine for disaster recovery, even when it gives you features like snapshot to freeze the disk state at one or multiple points in time.