User guide

In the SFAOS, host channels are referenced by Controller, Raid Processor, and Port values, and

in the example below VDs 0 to 3 are presented to all hosts through all host channels.

S2A 6620 models have 4 Fibre Channel Ports.

The WebUI illustrates enabled host channels on which the presentations will be available:

5. PERFORMANCE CONSIDERATIONS FOR SFA 10000

To achieve optimal performance on SFA 10000 appliances, it is important to make note that the

pool home attribute is assigned to raid processors (RP’s), not to controllers as in the case of S2A

6620 and S2A 9900. This design feature requires special consideration when optimizing

multipath performance.

The example below illustrates pool priority values reported by the SFA10k prioritizer provided

as part of the DDN linux multipath RPM. In this example, four pools are shown with

color-coding that matches the pool ownership defined in the example.

The most optimal path will always be a host port belonging to the home RP for the VD and

underlying pool of any given presented LUN. The second most optimal path will be the peer RP

in the same controller as the home RP. The third most optimal choice is always RP0 of the peer

controller. The least optimal RP is always RP1 of the peer controller. The DDN linux multipath

SFA10k prioritizer determines the topology of each path and reports a priority value for each

path with values of 100,90,20 and 10 reflecting the four RP priorities.