Fibre Channel (SAN)

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Occasional Contributor
Posts: 17
Registered: ‎10-27-2008

Understanding Port Statistics

Is there a guide/documentation that explains what the different "port statistics" mean within the "port admin window"?  Specifically, I would like to know what C2 and C3 frames are and all the other categories within the tabs of the port stats window.  This is on 48000.  Thanks in advanced,

Super Contributor
Posts: 425
Registered: ‎03-03-2010

Re: Understanding Port Statistics

pls find the doc that may help you. you have to go to find the details of the cmd. pls make the thread correct if you find it.

Super Contributor
Posts: 260
Registered: ‎04-09-2008

Re: Understanding Port Statistics

DO NOT ATTACH FILES WITH SPACE IN IT, NO ONE WILL BE ABLE TO DOWNLOAD IT

This tip has been compiled from various sources with inputs from my understanding. Use CLI for troubleshooting port errors preferably.
the output of porterrshow can be bifurcated into 2 areas,
1. Physical layer issues, these originate at the source and can propagate through fabrics.
enc_in: This counter increments when 8b/10b encoding errors are detected within a frame. enc_in errors are always detected on the ingress port.
crc_err: Indicates corruption within the frame. Always seen on ingress port but will be passed by the switch unaltered through the fabric.
enc_in and/or crc_err = Possible bad media (SFP, cable, patch panel)
Bad_eof: After a loss of synchronization error, continuous-mode alignment allows the receiver to re-establish word alignment at any point in the incoming bit stream
while the receiver is operational. If such a re-alignment occurs, detection of the resulting error condition is dependant upon higher level functions (eg: invalid CRC,
missing EOF)
my take if you see bad_eof and crc incrementing, replace SFP a.s.a.p
too_long or too_short errors indicate an unreliable link
enc_out: 8b/10b encoding errors NOT associated with frames (IDLE, R_RDY, and various other primitives). This counter increments during speed negotiation prior to login. Locking a port to a speed supported by the end device can be used to isolate issues.
– Possible bad media (SFP, cable, patch panel)
– Can cause a performance problem due to buffer recovery
disc_c3: Class 3 frame has been discarded because it is not routable to a destination address
– Corrupted or not-online Destination ID (DID)
– Timeout exceeded (Condor ASIC hold time exceeded)
– Counter may increment when FC nodes and/or switches rapidly transition between online and offline; look at fabriclog –s output
2. Link errors point to point - do not traverse fabric.
Link failures - error conditions that cause a port to drop out of an active state
– Requires the reconnecting device to FLOGI back into fabric (No speed negotiation required, since the device does not lose synchronization)
Loss of sync - occur when bit and word synchronization on link is lost
Loss of signal – occur when light or an electrical signal is lost on a link
– Require connected device to renegotiate speed and FLOGI back into fabric
If you experience device connectivity and/or performance issues and rising link counters look for
– bad cables/SFPs/patch-panel connections
– repeating cycles of online/offline states in fabriclog -s output
Once you identify the suspects use, portstats64show and portstatsshow to zero down on the culprit.
If you see errors on an ISL port and want to determine if source of dest is causing the error,
To find out if source or destination SFP is causing the error, Check the Output of "portshow x" where x is the port number.
If the pair of "Lr_in " and "Ols_out " as well the "Lr_out " and "Ols_in " values are "quite" equal, it is a normal case.
If one counter is significantly higher than the other, the link problems either "reached" the switch ("in" > "out") or are caused by the switch ("out" > "in").
Note: If the “Ols_in ? value is higher than the “Lr_out ? one, then the “problem source? is, in most cases, more related to the attached device (sending those offline sequences) and the switch responds to them with a "link reset".

Occasional Contributor
Posts: 17
Registered: ‎10-27-2008

Re: Understanding Port Statistics

Thanks for the doc!

Occasional Contributor
Posts: 17
Registered: ‎10-27-2008

Re: Understanding Port Statistics

Thanks for your post!  This helps...

Super Contributor
Posts: 425
Registered: ‎03-03-2010

Re: Understanding Port Statistics

pls make the thread correct

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