HP StorageWorks 2.64 Director Switch - Manual (Page 96)

Configuring the director 96
NOTE: Set the same value for R_A_TOV on all directors and switches in a multiswitch fabric. If the
value is not the same on all units, the fabric segments. Also, the value for R_A_TOV must be greater
than the value configured for E_D_TOV.
E_D_TOV
Adjust the E_D_TOV in tenth-of-a-second increments. An error condition occurs when an expected
response is not received within the time limit set by this value. The default value is 20 tenths (2
seconds). Set a value between 2 tenths through 600 tenths (.2 through 60 seconds).
NOTE: Set the same value for E_D_TOV on all directors and directors in a multiswitch fabric. If the
value is not the same, the fabric segments.
Switch Priority
Setting this value determines the principal director for the multiswitch fabric. Click Principal (highest
priority), Default, or Never Principal (lowest priority) on the Switch Priority drop-down list.
Setting these priority values determines the principal director selected for the multiswitch fabric. For
example, if you have three directors in the fabric and set one as Principal, one as Default, and one
as Never Principal, the unit set to Principal becomes the principal director in the fabric.
If all directors are set to Principal or Default, the director with the highest priority and the lowest
WWN becomes the principal director. Following are some examples of principal director selection
when directors have these settings:
• If you have three directors and set all to Default, the director with the lowest WWN becomes
the principal director.
• If you have three directors and set two to Principal and one to Default, the director with the
Principal setting that has the lowest WWN becomes the principal director.
• If you have three directors and set two to Default and one to Never Principal, the director with
the Default setting and the lowest WWN becomes the principal director.
At least one director in a multiswitch fabric needs to be set as Principal or Default. If all of the
directors are set to Never Principal, all of the interswitch links (ISLs) will segment. If all but one
director is set to Never Principal and the director that was principal goes offline, then all of the
other ISLs will segment.
NOTE: We recommend you leave the switch priority setting as Default. If you are considering
setting this value to something other than default, refer to the section on principal switch selection
for multiswitch fabrics in the HP StorageWorks SAN High Availability planning guide for details.