EMC Storage Product Knowledge Sharing

EMC recommends no more than four connectrix switches per fabric based on the following formulae:

One Switch

-32 Total ports
- 4 ports reserved for card failure
28 ports remaining.
- (int(28/5)) No more than 4:1 ratio, hosts : fa
23 Possible host connections
-2 to support multi-pathing
-11 total host connections


Two Switch

- 64 Total ports
- 4 ports reserved for card failure
- 4 ports reserved for E_ports
- 56 ports remaining.
-(int(56/5)) No more than 4:1 ratio, hosts : fa
-45 Possible host connections
-/ 2 to support multi-pathing
22 host connections (gain of 11)

Three switches

- 96 total ports
- 4 ports reserved for card failure
- 12 ports reserved for E_ports
-80 ports remaining
- (int(80/5)) No more than 4:1 ratio, hosts : fa
-64 Possible host connections
-/ 2 to support multi-pathing
-32 host connections (gain of 10)

Four switches
-128 total ports
- 4 ports reserved for card failure
- 24 ports reserved for E_ports
-100 ports remaining
- (int(100/5)) No more than 4:1 ratio, hosts : fa
-80 Possible host connections
- / 2 to support multi-pathing
-40 host connections (gain of 8)


Putting in that fourth connectrix means that you gain only 8 host connections from a 32 port connectrix switch.