MIME-Version: 1.0
From: Goran <sendmailtogoran@gmail.com>
Date: Fri, 11 May 2018 12:21:59 +0200
Message-ID: <CABS5c+GR6xJwV6im=N36Qmax-P6ZWrJYwDDVdekF3LWQ0tToXw@mail.gmail.com>
Subject: unstable nfs connection
To: linux-nfs@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Sender: linux-nfs-owner@vger.kernel.org

I have an issue with nfs which I'm using the first time.

I have a server running arch linux. Further the server is running
several container, each container itself is running arch linux too.
One container is running nfsd.

The nfs-container is connected via a virtual bridge. The bridge is
hosted by the server. One physical device is connected to that bridge.
A physical switch is connected to that physical device. The client is
connected to the physical switch.

To keep it simpler:
client -- clients NIC -- physical switch -- server NIC -- server
bridge -- container NIC -- container

At first sight, everything works well, I can boot diskless/readonly
from NFS. I use dracut for that. I can log into the client and start
working.

If the client is just doing nothing I get after some time (e.g. 5 minutes)

nfs: server 172.17.0.5 not responding. still trying

or

nfs: server 172.17.0.5 not responding.timed out

If 10 clients starts at same time, the above error comes immediatly.

I took a look like at the containers nic

23: eth0@if24: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc
noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 42:3b:82:03:c0:7d brd ff:ff:ff:ff:ff:ff link-netnsid 0
    RX: bytes  packets  errors  dropped overrun mcast
    44184595   388170   0       205     0       0
    TX: bytes  packets  errors  dropped carrier collsns
    902023963  112922   0       0       0       0

but this seems not too much dropped packages for me. I'm more a C++
guy, not as much an Linux admin. So I'm asking how can I debug this
nfs-connection to make it stable?

Regards
Goran