Databases distributed across 20 disks on 6 nodes. Each database has a container with the encapsulation of the legacy event record. Another contains metadata on each event record. Each metadata tag is about 250 Bytes per event. The event size is 5 kBytes.
Event data is no. of tracks, thrust, total visible energy etc.
There is a bit array, like a mask, that the Tau people use to set features. Each database is 20 Mbytes. Each also has run objects with a one to many association with the tag data for events in the run. There are many run objects in the database. Things like the beam energy, magnetic field, are also stored.