Fibre Channel (SAN)

New Contributor
Posts: 2
Registered: ‎09-19-2012

Communication Issues at 8GB. Works Great at 4GB

Looking for some advise as where to start troubleshooting this issue. This is a new setup.

The Setup. Primary Data Center SAN Connected to a two Brocade 300 switches. One port on the one switch has a Brocade 8GB 10Km Sfp purchased. At the Secondary Data Center we have a Single Brocade 300 switch with a attached SAN which also has a Brocade 8GB <10KM SFP.There is a dark fibre link that connects both of these together. There is no switching in between these at all, with the exception of a couple patch panels. The distance between the two sites is 4Km. When the Ports are set at 8GB(AutoNeg) or Hard Coded, I can move data, but its very very slow. 20MB/Sec. I see alot of CRC errors and invalid Transmited Word and started seeing a Warning on the Destination Brocade switch "Severe latency bottleneck detected at slot 0 port 7". YEs port 7 is the 10Km link. Also, around the same time the SAN links had flapped and had this same "Invalid Transmitted word type".  Was suggested I run the following two commands on both sides.

portcfgfillword <PORT> 3

portcfglongdistance <PORT> LE 1

CRC ERORRS went away but still had "Invalid transmitted word type" and the same lack of speed. 20MB/SEC. Had coded one side too 4GB and the other side picked up the 4GB link. Cleared counters. And transfered 1TB of data accross the link. Was super nice. 100MB +/sec moving data. Where too start? Any Ideas?

Thanks .

Regular Contributor
Posts: 226
Registered: ‎01-08-2011

Re: Communication Issues at 8GB. Works Great at 4GB

Hi, you could experiment with the other settings on portcfgfillword - at least with end-devices it's not always the same setting.

Do you have 8Gb end-devices too? Perhaps you need to configure proper fill-word there too.

In the CMD reference it says that if you use QoS you should not use vc_init (the 1 in your portcfglondistance command).

New Contributor
Posts: 2
Registered: ‎09-19-2012

Re: Communication Issues at 8GB. Works Great at 4GB

The end devices are SAN Fibre connections which are 8GB as well. I never did set any setting on those ports as i figured those were suppose to work right out of the box. Maybe I assumed wrong.

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