Availability; Maximum-Availability Example - EMC Connectrix EC-1200 Planning Manual

Availability

Figure A-1
Good topology design minimizes the impact of an interruption
caused by a failed component. To accomplish this, the design
considers the end-to-end channel. End-to-end analysis begins with
the HBA, a link to the switch, the components of the switch
(particularly the port cards), the link to the storage, and the Fibre
Channel director in the Symmetrix. The design options are
categorized into maximum-availability (the recommended strategy)
and high-availability strategies.
Maximum availability (see Figure A-1) is achieved using the dual
fabrics of a Connectrix Balanced Fabric. For clarity in this
explanation, assume the devices are named Fabric A and Fabric B:
On the host side of the switch, each server has two adapters and
uses PowerPath. The physical topology is designed such that each
HBA (HBA-A and HBA-B) in one server is interconnected with its
respective A and B ED-64M. (This topology is typical of
mainframe ESCON director installations.)
On the storage side of the switch, the A and B ports of each
Symmetrix Fibre Channel director (FA) are connected to
respective A and B fabric ports.
Fabric
HBA-A
A
Sun Server
with
PowerPath
Fabric
B
HBA-B

Maximum-Availability Example

High availability (see Figure A-2) is achieved with a single ED-64M
where the A and B halves of the environment are segregated across
port cards:
On the host side of the switch, the two HBAs under one server
with PowerPath, are connected to different port cards.
On the storage side of the switch, the A and B of each Fibre
Channel director are connected to different port cards.
How to Design a Solution
Symmetrix
FA-1A
FA-5A
Availability
A-3
A