@mina@pmj at least TB and many millions of access per day.
The monster is the data centre. About 20 years ago I was allowed to a tour to the company mainframe. The floor was about the size of gym (Turnhalle) in the centre of the room were 2 closets size computer and a third of the room was filled with disks https://youtu.be/RnpvyJaX4Q4?feature=shared so here you see the assembly of a mainframe