How equipment is arranged.
WHAT A RACK IS
A standardised frame holding equipment.
WHAT A UNIT IS
The standard height measurement for rack-mounted equipment.
A server may occupy one, two or more.
WHAT A STANDARD RACK HOLDS
Roughly forty-two units, in a full-height cabinet.
WHAT ELSE GOES IN A RACK
Network switches Power distribution units Cable management Sometimes battery backup
WHY STANDARDISATION MATTERS
Equipment from any manufacturer fits any rack.
WHAT LIMITS WHAT YOU CAN FIT
Power available to the rack Cooling capacity Weight, in some buildings
THAT FIRST ONE AGAIN
A rack is rarely filled to capacity, because the power runs out first.
WHAT TO PLAN
Power per rack, before counting units.
WHAT TO CONSIDER
Cable management, which affects airflow and maintainability.
WHAT TO LABEL
Everything: equipment, cables at both ends, ports.
WHY
Because in a failure, at night, nobody remembers.
