thanks guys for all your help.

looks like the issue is fundamentally poor performance across 100GbE, where I'm 
only
getting ~50Gb/s using iperf. I believe the MTU is set correctly across all my 
systems
Using connectx-4 in 100GbE mode.

thanks again,
-john



On 11/28/17 9:03 PM, Colin Faber wrote:
Are peer credits set appropriately across your fabric?

On Nov 28, 2017 8:40 PM, "john casu" <[email protected] 
<mailto:[email protected]>> wrote:

    Thanks,
    just about to try that MTU setting.

    It's a small lustre system... 2 routers, MDS/MGS pair, OSS pair, JBOD pair 
(112 drives for OST)
    and yes, routing between EDR & 100GbE

    -john

    On 11/28/17 7:28 PM, Raj wrote:

        John, increasing MTU size on Ethernet side should increase the b/w. I 
also have a feeling that some lnet routers and/or
        intermediate switches/routers does not have jumbo frame turned on (some 
switches needs to be set at 9212 bytes ).
        How many LNet  routers are you using? I believe you are routing between 
EDR IB and 100GbE.


        On Tue, Nov 28, 2017 at 7:21 PM John Casu <[email protected] 
<mailto:[email protected]> <mailto:[email protected] 
<mailto:[email protected]>>> wrote:

             just built a system w. lnet routers that bridge Infiniband & 
100GbE, using Centos built in Infiniband support
             servers are Infiniband, clients are 100GbE (connectx-4 cards)

             my direct write performance from clients over Infiniband is around 
15GB/s

             When I introduced the lnet routers, performance dropped to 10GB/s

             Thought the problem was an MTU of 1500, but when I changed the 
MTUs to 9000
             performance dropped to 3GB/s.

             When I tuned according to John Fragella's LUG slides, things went 
even slower (1.5GB/s write)

             does anyone have any ideas on what I'm doing wrong??

             thanks,
             -john c.

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