[CentOS] gigE -> 100Mb problems

[John R Pierce]

On 10/11/2016 9:03 PM, Ashish Yadav wrote:
> Please test that if both the server are communicating with each other at
> 1Gbps or not via "iperf" tool.
>
> If above gives result of 1Gbps then it will eliminate the NICs problem then
> you know that it is a problem with cisco switch only.

after they forced the cisco ports to gigE, I was seeing 200-400Mbps in 
iPerf, which was odd.  servers were both very lightly loaded.

BUT...   the switch ports kept going offline on us.   Note I have no 
admin access to the switch, its managed by IT so I have to go through 
channels to get anything.   I asked what error codes were causing the 
ports to go offline but haven't heard back.   as of right now, both 
servers are offline, (I can reach their IPMI management controller, and 
remotely log onto the console just fine, but the ports show no link).    
When I was in the DC yesterday, I switched ports, same problem, I also 
switched the network cable with a different (HP) server, it had no 
problems on the same cable+port thats giving these supermicro servers 
problems.

I'd chalk it up to a bad NIC, but two identical servers with two nic's 
each all have this problem,  so its got to be something else, some 
weirdness with the 82574L as implemented on these SuperMicro X8DTE-F 
servers running CentOS 6.7 ?!?    In our old DC, these servers ran rock 
solid for several years without any network issues at all, in that rack 
I had a Netgear JGS524




-- 
john r pierce, recycling bits in santa cruz