Brocade Fabric OS Command Reference Manual Supporting Fabric OS v6.4.0 (53-1001764-01, March 2010)

Fabric OS Command Reference 69
53-1001764-01
bottleneckMon
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bottleneckMon
Monitors and reports latency and congestion bottlenecks on F_Ports and E_Ports.
Synopsis bottleneckmon --enable [ -cthresh congestion_threshold] [-lthresh latency_threshold] [
-time seconds] [-qtime seconds] [-alert | -noalert]
bottleneckmon --disable
bottleneckmon --config [-cthresh congestion_threshold] [-lthresh latency_threshold]
[-time seconds][-qtime seconds] [[slot]port_list] [-alert | -noalert]
bottleneckmon --configclear [slot]port_list
bottleneckmon --exclude [slot]port_list
bottleneckmon --include [slot]port_list
bottleneckmon --show [-interval seconds] [-span seconds] [-refresh]
[-congestion | -latency ] [[slot/]port | *]
bottleneckmon --status
bottleneckmon --help
Description Use this command to monitor latency and congestion bottlenecks on F[L]_Ports and E_Ports. The
configuration options supported by this command include the following management functions:
• Enabling or disabling bottleneck monitoring on a switch and optionally configuring thresholds
and alert parameters.
• Changing alert parameters on specified ports after you have enabled the feature on the switch.
• Configuring severity thresholds for congestion and latency bottlenecks for a switch or for a
specified port list.
• Clearing the configuration on specified ports only (this option cannot be performed
switch-wide).
• Excluding specified ports from being monitored or including previously excluded ports.
• Generating history or status reports that show congestion bottlenecks and latency bottlenecks.
In Fabric OS v6.4.0 and later, enabling or disabling bottleneck monitoring is a switch-wide
operation. If Virtual Fabrics are enabled, the configuration is applied per logical switch and affects
all ports on the current logical switch. After the (logical) switch-wide bottleneck monitoring
parameters have been set, you can you can fine-tune the configuration for specific ports.
A bottleneck is defined as a condition where the offered load at a given port exceeds the
throughput at the port. This command supports detection of two types of bottleneck conditions:
congestion and latency.
• A congestion bottleneck arises from link over-utilization. This happens when the offered load
exceeds throughput and throughput is at 100%. Frames attempt to egress at a faster rate than
the line rate allows. Link utilization is measured once every second at the port (or when
trunked ports are monitored at the trunk master). A congestion bottleneck is assumed if the
utilization during the measured second is 95% or more.
• A latency bottleneck occurs when egress throughput at a port is lower than the offered load
because of latency in the return of credits from the other end of the link. This is not a
permanent condition. The offered load exceeds throughput and throughput is less than 100%.
In this case, the load does not exceed the physical capacity of the channel as such, but can