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Fabric Availability
The fabric is divided into four performance regions as follows:
•
Local Tier 1 devices - A video server application with I/O
capabilities of 40 MBps and 2,000 IOPS must be connected to the
fabric. Because the application is critical and high bandwidth (in
excess of 35 MBps), the server and associated storage are directly
attached to the core director as Tier 1 devices. No ISLs are used
for server-to-storage connectivity.
•
11 to 1 fan-out region - Eleven NT servers with I/O capabilities of
10 MBps and 1,000 IOPS are fabric-attached through a 32-port
edge switch. The primary applications are e-mail and online
transaction processing (OLTP). Because bandwidth use is light
and noncritical, the servers are connected to the core director with
a single ISL that is intentionally oversubscribed (1.1 Gbps plus
Class F traffic). The servers are connected to storage devices with
I/O capabilities of 11,000 IOPS.
•
6 to 1 fan-out region - Six servers with I/O capabilities of 20
MBps and 1,500 IOPS are fabric-attached through a 16-port edge
switch. Bandwidth use is light to medium but critical, so the
servers are connected to the core director with two ISLs (0.6 Gbps
each plus Class F traffic). The servers are connected to storage
devices with I/O capabilities of 9,000 IOPS.
•
3 to 1 fan-out region - Three servers with I/O capabilities of 30
MBps and 2,000 IOPS are fabric-attached through a 16-port edge
switch. Bandwidth use is medium but non critical, so the servers
are connected to the core director with one ISL (0.9 Gbps plus
Class F traffic). The servers are connected to storage devices with
I/O capabilities of 6,000 IOPS.
Many fabric-attached devices require highly-available connectivity to
support applications such as disk mirroring, server clustering, or
business continuance operations. High availability is accomplished
by deploying a resilient fabric topology or redundant fabrics.
A fabric topology that provides at least two internal routes between
fabric elements is considered resilient. A single director, switch, or
ISL failure does not affect the remaining elements and the overall
fabric remains operational. However, unforeseen events such as
human error, software failure, or disaster can cause the failure of a
single resilient fabric. Using redundant fabrics (with resiliency)
mitigates these effects and significantly increases fabric availability.
Planning Considerations for Fibre Channel Topologies
Planning Considerations for Fibre Channel Topologies
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