Brocade Network Advisor SAN + IP User Manual v12.1.0 - Manual (Page 1536)

Brocade Network Advisor SAN + IP User Manual 1489
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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 640 . In the figure, port15 and port22 are bottlenecked.
FIGURE 640 Bottleneck port indications
Limitations of bottleneck detection
The bottleneck detection feature for latency detection is not recommended for link utilizations
above 85 percent.
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.
Enabling bottleneck alerts and configuring alert parameters
Bottleneck detection is enabled on a switch or fabric basis. It enables both latency and congestion
detection. Consider these points when enabling bottleneck detection:
• If you enable bottleneck detection on a fabric, the feature is applied to all eligible switches in
the fabric and all eligible ports on the switches.
• If you enable bottleneck detection on a switch, the feature is applied to all eligible ports on that
switch.
• You can override switch configuration by changing parameters for specific ports.