Dell POWEREDGE M1000E - Manual (Page 102)

70 Fabric OS Command Reference
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bottleneckMon
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occur because of an underperforming device connected to the F_Port, or because of back
pressure from other congestion or latency bottlenecks on the E_Ports. Bottleneck monitoring
can help identify these devices and pinpoint the upstream bottlenecks caused by these
devices inside the fabric.
When bottleneck monitoring is enabled on a switch and -alert is specified, the command triggers
an SNMP and a RASlog alert when the ports on the configured switch experience latency or
congestion. Another alert is sent after the condition resolves. For a given averaging time, each
second is marked as affected by latency and/or congestion or not. If the number of affected
seconds crosses the configured threshold, an alert is triggered for the port. You can configure a
severity threshold for each type of bottleneck and the time interval over which the bottlenecks are
measured.
For example, setting a latency threshold of 0.8 and a time window of 30 seconds specifies that an
alert should be sent when 80% of the one-second samples over any period of 30 seconds were
affected by latency bottleneck conditions. The -qtime option can be used to throttle alerts by
specifying the minimum number of seconds between consecutive alerts. Thresholds are configured
separately for each type of bottleneck and statistical data are collected independently for each
condition. The -qtime parameter applies to both types of bottleneck monitoring; there can be one
latency alert and one congestion alert in a configured quiet time.
Bottleneck monitoring works both in non-Virtual Fabric mode and in Virtual Fabric Mode. If Virtual
Fabrics are enabled, bottleneck monitoring is configured per logical switch. If a port is removed
from a logical switch after bottleneck detection is enabled on the logical switch, the configuration is
retained in that logical switch. If the port is added again to the same logical switch, bottleneck
detection is automatically re-enabled for this port using the retained configuration. This feature
allows you to configure more than one logical switch to perform bottleneck detection on the same
port, although only one logical switch performs the operation on the port at any given time.
The --show option displays a history of the bottleneck severity for a specified port or for all ports.
Each line of output shows the percentage of one-second intervals affected by bottleneck conditions
during the time window shown on that line. When issued for all ports, the union of all port statistics
is displayed in addition to individual port statistics. The union value provides a good indicator for
the overall bottleneck severity on the switch. You can filter the output to display only latency or
congestion bottleneck statistics. When used without port operand the command displays the
number of ports affected by bottleneck conditions. A “bottlenecked” port in this output is defined
as any port that was affected by a bottleneck for one second or more in the corresponding interval.
The --status option displays bottleneck configuration details for the current (logical) switch. If
virtual fabrics are enabled, ports not belonging to the current logical switch are not displayed. This
is change from v6.3.0, where the output of --status included ports that did not belong to the
current logical switch. The command output includes the following information:
Bottleneck detection
Enabled or disabled
Switch-wide alerting parameters
Alerts? Yes (enabled) or No (disabled)
Congestion threshold for alert
The severity threshold for triggering a congestion alert. This threshold
indicates the percentage of one-second intervals affected by congestion
conditions within a specified time window. The congestion threshold is
expressed as a fraction between 0 and 1.