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Bottlenecks on ISL's

  • 1.  Bottlenecks on ISL's

    Posted 05-12-2015 02:28 AM

    Hi everyone,

     

    a switch in my fabric is reporting errors regarding bottlenecks on ports that are used for ISL.

    Normally, the fabric works well, but when some operations with high IOPS load are being performed, we are experiencing problems on the whole environment.

    The switch is Brocade 5300 provided by IBM, FOS version is 7.2.1d.

    The ports used for ISL are 36-39.

    36 36 012400 id N8 Online FC E-Port 10:00:00:05:33:fa:6e:a6 "SAN80B-3__2498-12" (downstream)(Trunk master)
    37 37 012500 id N8 Online FC E-Port (Trunk port, master is Port 36 )
    38 38 012600 id N8 Online FC E-Port (Trunk port, master is Port 36 )
    39 39 012700 id N8 Online FC E-Port (Trunk port, master is Port 36 )

    Here is the info from Brocade SAN Health report which was gathered during the problems with our environment:

    IBM_FC_SAN80B-1 1 36 36 SAN80B-3__2498-12 9 36 36 Trunk Master 500 1 D 8 Gbps 32 15.6 MB/s 1% 123.6 MB/s 8%
    IBM_FC_SAN80B-1 1 38 38 SAN80B-3__2498-12 9 38 38 Trunk Slave 8 Gbps 8 124 MB/s 8% 449.8 MB/s 28%
    IBM_FC_SAN80B-1 1 37 37 SAN80B-3__2498-12 9 37 37 Trunk Slave 8 Gbps 8 39.4 MB/s 2% 212.6 MB/s 13%
    IBM_FC_SAN80B-1 1 39 39 SAN80B-3__2498-12 9 39 39 Trunk Slave 8 Gbps 8 342.3 MB/s 21% 983.1 MB/s 61%

     

    -------

     

    36 36 SAN80B-3__2498-12 10:00:00:05:33:fa:6e:a6 685.5m 4.2g 0 0 0 0 0 0 665.3k 0 0 0 0 0 15.6 MB 123.6 MB
    37 37 Trunk slave master is Port 36 529.5m 1.3g 0 0 0 0 0 0 1.5m 0 0 0 0 0 39.4 MB 212.6 MB
    38 38 Trunk slave master is Port 36 682.3m 4.1g 0 0 0 0 0 0 385.6k 0 0 0 0 0 124 MB 449.8 MB
    39 39 Trunk slave master is Port 36 1.3g 1.2g 0 0 0 0 0 0 2.5m 0 0 0 0 0 342.3 MB 983.1 MB

     

    --------

     

    I see that the number of disc_c3 is incredibly high:

    665.3k  for port 36
    1.5m for port 37
    385.6k for port 38
    2.5m for port 39

     

    Is that what I should be looking at? What can be causing this? How can I solve the problem?


    #disc_c3
    #BrocadeFibreChannelNetworkingCommunity
    #isl
    #Bottleneck


  • 2.  Re: Bottlenecks on ISL's

    Posted 05-17-2015 12:36 AM

    Check connected host ( Target and Initiator ) ports.


    #BrocadeFibreChannelNetworkingCommunity


  • 3.  Re: Bottlenecks on ISL's

    Posted 05-21-2015 06:34 PM

    Can be any of two things. Congestion and/or latency. I suggest you start reading some of my blog-posts which have helped a fair few administrators to resolved their problems in this area.


    #BrocadeFibreChannelNetworkingCommunity