HP StorageWorks 64 - SAN Director Switch Planning Manual page 83

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After directors and edge switches are defined and cabled, they automatically join
to form a single fabric through a user-transparent process. However, the user
should be aware of the following fabric concepts, configuration characteristics,
and operational characteristics:
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SAN High Availability Planning Guide
Special consideration must also be given to applications with high data
transfer rates or devices that participate in frequent or critical data transfer
operations. For example, in
server and device D
9
nightly backup operation. HP recommends that such a connection be routed
directly through Director S
WWN-bound port connections. For additional information, refer to
Locality" on page 100.
Zoning — For multi-switch fabrics, zoning is configured on a fabric-wide
basis. Changes to the zoning configuration apply to all directors and switches
in the fabric. To ensure the zoning configuration is maintained, certain rules
are enforced when two or more elements are connected through ISLs to form
a fabric, or when two or more fabrics are joined. For additional information,
refer to "Configuring
Principal Switch selection — Setting this value determines the principal
switch for the multi-switch fabric. Select either Principal (highest priority),
Default, or Never Principal (lowest priority) from the Switch Priority
drop-down list. If all fabric elements are set to Principal or Default, the
director or switch with the highest priority and the lowest WWN becomes the
principal switch.
Following are examples of principal switch selection when fabric elements
have these settings.
— If you have three fabric elements and set all to Default, the director or
switch with the lowest WWN becomes the principal switch.
— If you have three fabric elements and set two to Principal and one to
Default, the element with the Principal setting that has the lowest WWN
becomes the principal switch.
— If you have three fabric elements and set two to Default and one to Never
Principal, the element with the Default setting and the lowest WWN
becomes the principal switch.
Planning Considerations for Fibre Channel Topologies
Figure 35 on page 78, suppose device D
is a storage unit and both devices participate in a critical
(rather than the entire fabric) through zoned or
2
Zones" on page 133.
is a
7
"Device
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