What is a switch role in VERITAS SANPoint Control (tm) and when does the switch role change?
SANPoint Control assigns two types of roles to all switches it discovers in a fabric. These roles are:
By default, SANPoint Control assigns the 'principal' role to the switch with the lowest (World Wide Name (WWN) in the fabric, and by default it assigns the fabric the name of the 'principal' switch thus discovered.
Suppose there are ten switches in the fabric. SANPoint Control will query all ten switches for WWN and pick the switch with the lowest WWN as the 'principal' switch and assign the "switch_name" of the 'principal' switch as the fabric name.
If the switch with the lowest WWN leaves the fabric, then SANPoint Control will query again and pick a new switch with the lowest WWN among the remaining switches to assign it the role of the new 'principal' switch.
For this reason, the user may want to manually assign a fabric name by using the fabric renaming feature in the SANPoint Control console. This is to avoid a change in fabric name in case the 'principal' switch has changed.
One way to change the 'principal' switch of a fabric is to reboot the 'principal' switch. When the 'principal' switch has been rebooted or removed, one of the 'subordinate' switches will assume the role of the 'principal' switch.
All switches in the fabric share information such as zoning tables and a reassignment of 'principal' switch role does not cause a loss of information. The zone explorer, for example, periodically rescans the fabric and updates zoning information based on reading the zone information from all of the switches in the fabric.
In case there is only one switch in the fabric and this switch 'goes away' then SANPoint Control would delete the fabric that has 'gone away.' If a fabric has 'gone away' based on that rule, SANPoint Control would use the SAN Access Layer (SAL) delete object call to delete the fabric.