Brocade Network Advisor SAN User Manual v11.1x (53-1002167-01, May 2011)

Brocade Network Advisor SAN User Manual 801

53-1002167-01

Bottleneck detection

• Bottleneck detection is supported on 4 Gbps, 8 Gbps, and 16 Gbps platforms.

• Bottleneck detection is supported in Access Gateway mode.

• 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 351. In the figure, port15 and port22 are bottlenecked.

FIGURE 351 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 CEE side, and does not monitor

traffic going in the reverse direction.

Enabling bottleneck detection

Bottleneck detection is enabled on a switch or fabric basis.

• 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.

If ineligible ports later become eligible or, in the case of a logical switch, if ports are moved to the

logical switch, bottleneck detection is automatically applied to those ports.