Monitor the performance metrics that are collected for physical switches, switch ports,
and inter-switch
connections.
Performance metrics for switches are divided
into the following categories:
Table 1. Key
port metrics
| Metric |
Description |
| Bandwidth Percentage (Send) |
The percentage of the
port bandwidth that is used for send operations. This value is an
indicator of port bandwidth usage that is based on the speed of the
port. |
| Bandwidth Percentage (Receive) |
The percentage of
the port bandwidth that is used for receive operations. This value
is an indicator of port bandwidth usage that is based on the speed
of the port. |
| Bandwidth Percentage (Overall) |
The percentage of the port bandwidth that is used
for send and receive operations. This value is an indicator of port bandwidth usage that is based on
the speed of the port. |
| Data Rate (Send) |
The average rate at which data is sent by the port. A send operation is a read
operation that is processed, or a write operation that is initiated by the port. The rate is
measured in MiB per second. |
| Data Rate (Receive) |
The average rate at which data is received by the port. A receive operation is
a write operation that is processed, or a read operation that is initiated by the port. The rate is
measured in MiB per second. |
| Data Rate (Total) |
The average rate at which
data is transferred through the port. The rate is measured in MiB
per second and includes both send and receive operations. |
| Total Port Error Rate |
The average number of times per second that
an error was detected on the port. This rate is a summation of all
the other error rates for the port. |
Table 2. I/O rates
| Metric |
Description |
| Port Frame Rate (Send) |
The average number of frames per second that are sent by
the port. |
| Port Frame Rate (Receive) |
The average number
of frames per second that are received by the port. |
| Port Frame Rate (Total) |
The average number of frames per second that are
transferred. This value includes frames that are sent and received by the port. |
Table 3. Peak data
rates
| Metric |
Description |
| Peak Data Rate (Send)1 |
The highest rate at which data is sent by the port. A send operation is a read
operation that is processed, or a write operation that is initiated by the port. |
| Peak Data Rate (Receive)1 |
The highest rate at which data is received by the port. A receive operation is
a write operation that is processed, or a read operation that is initiated by the port. |
Notes:
- This metric is only available for
ports on Brocade switches. You must use an SMI agent to collect data for this metric. In the Storage
Management Initiative Specification (SMI-S), peak data rates for a port are reported in the
CIM_FcPortRateStatistics class. For SMI-S Version 1.1, this is an optional class, meaning that it
might not be supported by a given vendor. This can result in IBM
Spectrum Control displaying zeros for the peak rates, even
when there is non-zero traffic flowing through the port. When a vendor does support this class, the
peak data rate represents the peak value of the associated metric counter (as reported by the CIM
agent used to access the device) over a recent, vendor-defined measurement window (for example, 20
milliseconds) of the IBM
Spectrum Control measurement
window (for example, 15 minutes).
|
Table 4. Frame error rates
| Metric |
Description |
| Bad EOF CRC Error Rate1 |
The percentage
of nonsequential read operations that find data in the cache.You can use this
value to understand throughput or response times. Low cache-hit percentages
can increase response times because a cache miss requires access to
the back-end storage resources. |
| CRC Error Rate |
The percentage of
nonsequential write operations that are handled in the cache. |
| Discarded Class 3 Frame Rate |
The average number
of class 3 frames per second that are discarded. |
| Error Frame Rate1 |
The average number of error
frames per second that are received. An error frame is a frame that
violates the Fibre Channel Protocol. |
| F-BSY Frame Rate2 |
The average number of F-BSY
frames per second that are generated. An F-BSY frame is issued
by the fabric to indicate that a frame cannot be delivered because
the fabric or destination N_port is busy. |
| F-RJT Frame Rate2 |
The average number of F-RJT
frames per second that are generated.An F-RJT frame is issued
by the fabric to indicate that delivery of a frame was denied. |
| Long Frame Rate |
The average number of frames
that are received per second that are longer than 2140 octets. This
number excludes start-of-frame bytes and end-of-frame bytes. The 2140 octet limit is calculated
based on the assumption that a frame has 24 header bytes, 4 CRC bytes,
and 2112 data bytes. |
| Short Frame Rate2 |
The average number of frames
that are received per second that are shorter than 28 octets. This
number excludes start-of-frame bytes and end-of-frame bytes. The 28 octet limit is calculated
based on the assumption that a frame has 24 header bytes, and 4 CRC
bytes. |
Notes:
- This metric is only available
for ports on Brocade switches.
- This metric is only available for
ports on Cisco switches.
|
Table 5. Port protocol error
rates
| Metric |
Description |
| Class 3 Receive Timeout Frame Rate1 |
The average number
of class 3 frames per second that were discarded after reception because
of a timeout condition. The timeout condition occurs while a transmitting
port waits for buffer credit from a port at the other end of the fibre.
When you troubleshoot a SAN, use this metric to help identify port
conditions that might slow the performance of the resources to which
those ports are connected. |
| Class 3 Send Timeout Frame Rate1 |
The average number
of class 3 frames per second that were discarded before transmission
because of a timeout condition. The timeout condition occurs while
the switch or port waits for buffer credit from the receiving port
at the other end of the fibre. When you troubleshoot a SAN, use this
metric to help identify port conditions that might slow the performance
of the resources to which those ports are connected. |
| Credit Recovery Link Reset Rate |
The estimated average
number of link resets per second that a switch or port completed to
recover buffer credits. This estimate attempts to disregard link resets
that were caused by link initialization. When you troubleshoot a SAN,
use this metric to help identify port conditions that might slow the
performance of the resources to which those ports are connected. |
| Discarded Frame Rate1 |
The average number of
frames per second that are discarded because host buffers are unavailable
for the port. |
| Link Reset Received Rate |
The average number
of times per second that the port changes from an active (AC) state
to a Link Recovery (LR2) state. |
| Link Reset Transmitted Rate |
The average number
of times per second that the port changes from an active (AC) state
to a Link Recovery (LR1) state. |
| Port Congestion Index |
The estimated degree to which
frame transmission was delayed due to a lack of buffer credits. This
value is generally 0 - 100. The value 0 means there was no congestion.
The value can exceed 100 if the buffer credit exhaustion persisted
for an extended amount of time. When you troubleshoot a SAN, use this
metric to help identify port conditions that might slow the performance
of the resources to which those ports are connected. |
| Zero Buffer Credit Percentage |
The amount of
time, as a percentage, that the port was not able to send frames between
ports because of insufficient buffer-to-buffer credit. The amount
of time value is measured from the last time that the node was reset.
In Fibre Channel technology, buffer-to-buffer credit is used to control
the flow of frames between ports. |
| Zero Buffer Credit Rate |
The average number of Zero
Buffer Credit conditions per second that occurred. A Zero Buffer Credit
condition occurs when a port is unable to send frames because of a
lack of buffer credit since the last node reset. When you troubleshoot
a SAN, use this metric to help identify port conditions that might
slow the performance of the resources to which those ports are connected. |
Notes:
- This metric is available
only for ports on Brocade switches.
|
Table 6. Link error rates
| Metric |
Description |
| Encoding Disparity |
The average number
of disparity errors per second that are received. |
| Invalid Link Transmission Rate |
The average number
of times per second that an invalid transmission word was detected
by the port while the link did not experience any signal or synchronization
loss. |
| Invalid Word Transmission Rate |
The average
number of bit errors per second that are detected. |
| Link Failure Rate |
The average number of miscellaneous
fibre channel link errors per second for ports. Link errors might
occur when an unexpected Not Operational (NOS) is received or a link
state machine failure was detected. |
| Loss of Signal Rate |
The average number of times
per second at which the port lost communication with its partner port.
These types of errors usually indicate physical link problems, caused
by faulty SFP modules or cables, or caused by faulty connections at
the switch or patch panel. However, in some cases, this error can
also occur when the maximum link distance between ports is exceeded,
for the type of connecting cable and light source. |
| Loss of Sync Rate |
The average number of times
per second that the port lost synchronization with its partner port.
These types of errors usually indicate physical link problems, caused
by faulty SFP modules or cables, or caused by faulty connections at
the switch or patch panel. However in some cases this can also occur
due to mismatching port speeds between the partner ports, when auto-negotiation
of link speed is disabled. |
| Primitive Sequence Protocol Error Rate |
The
average number of primitive sequence protocol errors per second that
are detected. This
error occurs when there is a link failure for a port. |
Table 7. Miscellaneous port metrics
| Metric |
Description |
| Link Quality Percentage |
The percentage is based on whether the port
is an expansion port (E_port) or a fabric port (F_port), and on the
numbers and types of errors that are detected by the port. |
| Port Frame Size (Overall) |
The average frame transfer
size. This value is measured in KiB and includes frames that are sent
and frames that are received by the port. |
| Port Frame Size (Receive) |
The average size of
a frame, in KiB, that is received by the port. |
| Port Frame Size (Send) |
The average size of a frame,
in KiB, that is sent through the port. |