Connectrix Cisco MDS: How to configure switch priority for principal switch selection

Any new switch can become the principal switch when it joins a stable fabric. During the principal switch selection phase, the switch with the highest priority becomes the principal switch. If two switches have the same configured priority, the switch with the lowest World Wide Name (WWN) becomes the principal switch. 

By default, the configured priority is 128. The valid range of the priority is between 1 and 254. Priority 1 has the highest priority. A value of 255 is accepted from other switches but cannot be locally configured.

You can configure the priority value on the switch, for example, for Virtual Storage Area Networks (VSAN), using these steps:

switch # configure terminal
switch (config) # fcdomain priority x vsan vsan-id     {x is the priority value}

The priority configuration is applied to the runtime when the fcdomain is restarted. This configuration is applicable to both disruptive and non-disruptive restarts.

To restart the fabric non-disruptively in VSAN, use the following configuration steps:

switch # configure terminal
switch (config) # fcdomain restart vsan vsan-id

To restart the fabric disruptively, use the fcdomain restart disruptive vsan vsan-id command. This command causes all devices of all switches in that VSAN to log out, causing data traffic disruption.
 

See this video for more information: