Hi Trond,
You were right in that auto negotiation was the root of the problems,
but only some of them.
I did :
ethtool -s eth0 duplex full autoneg off speed 100
[235557.010306] igb: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow
Control: None
Seeing a big TCP performance boost (now it equals the UDP speed).
But I still have serious problems. I get :
[235809.364907] INFO: task dd:5858 blocked for more than 120 seconds.
[235809.377710] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
disables this message.
[...]
Trond, I think you were working with that with Ubuntu people right ?
I am using latest Ubuntu 10.04.2 kernel : 2.6.32-31-server
I might fix this bug with newer kernels or patches, but there's
another thing I cannot fix :
I get lots of :
nfs: server.dom.com is not responding, still trying
So I guess I will stick to default ethernet settings and UDP. It might
not be the fastest option, but it's the most trouble free setup (I
cross my fingers ...)
Thanks again.
Best,
David
On 29/04/2011, at 18:54, Trond Myklebust wrote:
On Fri, 2011-04-29 at 17:52 +0200, David McGiven wrote:
Chuck,
Thank you very much for the advice. I'm currently using wsize and
rsize of 1024 to avoid IP fragmentation. Strangely, UDP performs much
faster compared to TCP, no matter the size of rsize/wsize. I am
puzzled about that, but ...
The problem with the network troubleshoot is that I cannot change
anything in the path between the client and the server : 2 routers
and
a CISCO PIX (I don't know if it's one of this 2 hops or it's
invisible, but it's there for sure). While researching this problem
I've noticed that iperf shows extremely slow speed from client to
server LAN segments, while in the opposite way the speed is ok.
There's definitely something wrong there but I cannot change it
neither complain, so, let UDP be it, I'm satisfied enough with the
speed I get with rsize/wsize=1024. My main concern was about data
corruption.
Have you checked the autonegotiation settings on your NIC? 'ethtool
eth0' is your friend...
--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@xxxxxxxxxx
www.netapp.com
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