EMC Connectrix ED-64M, User Manual

Page: 140 / 476

5
5-12
Connectrix ED-64M User Guide
Configuring the Director
The principal switch is determined as follows:
◆
If one (and only one) director/switch is set to Principal, it
becomes the principal switch. This switch remains the principal
switch as long as it is on line in the fabric, even if someone
changes another switch’s Switch Priority to Principal.
◆
If more than one director/switch is set to Principal, the
director/switch with the lowest WWN number among those set
to Principal becomes the principal switch.
The Switch Priority setting for every other switch/director
(including any others that were previously set to Principal)
automatically changes to Default.
In some two-tier fabrics (consisting of backbone and edge switches), EMC
recommends configuring all backbone switches as Principal, to provide
backup in the event of a failure. (This prevents an edge switch from
becoming principal.) For more information, consult your EMC
representative.
◆
If no director/switch is set to Principal but one or more are set to
Default
, the director/switch with the lowest WWN number
among those set to Default becomes the principal switch.
The Switch Priority setting for every other switch/director
remains unchanged.
◆
If all directors/switches are set to Never Principal, no
director/switch can be principal. In this case, all of the ISLs will
segment, with reason code 05 (no switch is capable of becoming a
principal switch).
If all but one director/switch in the fabric is set to Never Principal,
and the principal switch goes off line, all remaining ISLs will
segment, with reason code 05.
If the principal switch was selected by WWN, adding a switch with a
lower WWN does not change the principal if the newly added switch
is set to Open Fabric 1.0 Interop Mode. (Refer to Interop Mode on
page 5-13.) This is because adding such a switch does not cause a
Build Fabric process. The next time a Build Fabric occurs, however,
the switch with the lowest WWN will become principal.
In some logs, Switch Priority settings map to numbers: Principal = 1,
Default
= 254, Never Principal = 255.