[18373207] Duo Slow NFS Reads, Jumbo Frames and TCP window

Well it was a bit more complicated than that - for those of us with factory standard software there is a need to install the ssh add-on, then install apt, then

apt-get update

to be able to get tcpdump.

Anyway figured that out and then the instructions above are perfect.

I have successfully captured some packets and have included the file here here for analysis (it's around 5mb).

I "think" I can see packet sizes greater than the 1500 MTU, as an example look at packet 6 which seems to be 42340 long

I can confirm than my NV+ is set up not to use jumbo frames - here's a picture to check. The host is connected by a 100mb network card to a gigabit switch, jumbo frames is not ticked on the readynas.



I'm typically getting around 12GB / hour on large scale transfers, whatever the protocol, which is equivalent to 3,333kb/s. I did see around 9000 kb/s after one setup change but it then fell back again

Hopefully this will help in getting those transfer rates up.

Hope someone can make sense of this