Specifications

3
Planning Considerations for Fibre Channel Topologies
3-35
Planning Considerations for Fibre Channel Topologies
Figure 3-14 Device Fan-Out Ratio
Performance Tuning When designing or tuning a fabric for performance, it is critical to
understand application I/O characteristics so that:
• Device output in Gbps does not oversubscribe ISLs, leading to
fabric congestion.
• Device output in IOPS does not result in a connectivity scheme
that exceeds fan-out ratios, leading to port congestion.
Figure 3-15 illustrates performance tuning for a simple fabric using
appropriate ISL connectivity, device locality, and fan-out regions for
device connectivity. The fabric is comprised of one core director and
six edge switches. Tier 2 servers connect to three switches at the
bottom of the figure, and Tier 2 storage devices connect to three
switches at the top of the figure.
T
M
T
M
Interswitch Link
Fabric Connection
1,000 IOPS
1,000 IOPS
1,000 IOPS
1,000 IOPS
1,000 IOPS
1,000 IOPS
10,000 IOPS
1,000 IOPS
1,000 IOPS
1,000 IOPS
1,000 IOPS
Device Fan-Out Ratio: 10 to 1