Brocade Communications Systems Network Advisor 12.0.0, User Manual

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Brocade Network Advisor SAN User Manual 923
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Bottleneck detection
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Bottleneck detection is supported whether Virtual Fabrics is enabled or disabled. In VF mode,
bottleneck detection is supported on all fabrics, including the base fabric.
How bottlenecks are reported
Bottlenecks are reported through alerts in the Master Log. A bottleneck cleared alert is sent when
the bottleneck is cleared.
NOTE
A bottleneck cleared alert is sent if you disable bottleneck detection on a bottlenecked port, even
though the port is still bottlenecked.
Bottlenecks can be highlighted in the Connectivity Map and Product List. Select Monitor >
Performance > View Bottlenecks. If a port is experiencing a bottleneck, a bottleneck icon is
displayed in the Connectivity Map for the switch and fabric, and in the Product List for the port,
switch, and fabric, as shown in
Figure 400 . In the figure, port15 and port22 are bottlenecked.
FIGURE 400 Bottleneck port indications
Limitations of bottleneck detection
Using this feature for latency bottleneck detection is not recommended for link utilizations above
85%.
The bottleneck detection feature detects latency bottlenecks only at the point of egress, not
ingress. For example, for E_Ports, only the traffic egressing the port is monitored. For FCoE ports,
bottleneck detection monitors traffic going from the FC side to the DCB side, and does not monitor
traffic going in the reverse direction.