Conditions That Favor Colocating

Each of the following conditions favors colocating applications with PFS I/O daemons.

• Large nodes (many CPUs per node).

• Fast disk-storage devices (storage arrays, for example) on each node.

• Lower-performance cluster interconnect, such as 10- or 100-BaseT Ethernet.

• Small number of applications competing for node resources.

When these conditions exist in combination, the network is more likely to be a performance-limiting resource than the relatively more powerful nodes. Therefore, it becomes advantageous to locate applications on the PFS I/O servers to decrease the amount of data that must be sent across the network.