Legacy HDS Forums

USP front-end port-server ratio

Discussion created by Legacy HDS Forums on Mar 5, 2008
Latest reply on Apr 18, 2008 by Legacy HDS Forums

Originally posted by: mrp

Is there a best practice or a fan-out/server-port ratio of how many hosts be connected to an USP front-end port.    I know i am just throwing a very generic question which has lots of "it depends".  Two things come to my mind when i try to size how many servers can sit on a port :

* IOPS rate for a USP port.  From documents i have read, it seems to indicate somewhere around 2500 IOPS is a good indication of need to spread load across more ports.
* Queue depths for a USP port.   I guess it's 1024 on USP.  so here it depends on number of hosts and number of LUNs attached to that port so that we not overrun port queue depth.

I consider the above two as a good rule of thumb to start with.    Is there anything that i should be aware of when deciding servers-port ratio or is there a recommended/best practice magic number like 8:1 fan-out ratio of servers-port.