4Gb channel strangly works only in 1Gb speed!

Hi all

I have installed SLES 11.3 on z10 lpar connected via 4 fiber channel to DMX3 control unit. on z10 and DMX3 sides both I can see the channels configured to work and are working on 4Gb.

unfortunately each channel will give me just 1Gb of throughput which I don’t know what could be the reason.

I check the IO by overal throuput reported by commands such as dd, fio, and specially atop. I asked the hardware staff to get me more channels and by adding 1 channel each time I noticed that the MB W/s reported by atop have increased by nearly 100 MB/s.

this evidences made me to decide each channel just work on 1Gb/s speed.

Does any body have any idea where the problem(not completely using channel speed) could be.

I am using the native multipath.

kindly regards


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