This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


[Xen-users] Problem of Xen in Combination with NFS

To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-users] Problem of Xen in Combination with NFS
From: jm-ml <jm-ml@xxxxxxxxx>
Date: Sat, 24 May 2008 23:58:13 +0200
Delivery-date: Sat, 24 May 2008 14:58:45 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird (Windows/20080421)
Juche List,

here is what I found out today. This Error was reproducable on two different machines, and I cannot think of the reason for the Problem, maybe I should post it on some NFS list, thats what I'll try next, but first I try here.

I use NFS to communicate data between dom0 and domU. I export some folder in dom0 and mount that export as /home in domU

When I write data from domU into /home the system looses its Network Connection (writing data from domU --> dom0). Strangely that only happens with files bigger then 200kB. There is no problem to write e.g. 50 kB into /home.

I can still login on xm console domU but after some moments the system can only be shut down using xm destroy domU.

If I try to recreate domU i get the error:

Using config file "/home/vserver/springfield/start-springfield".
Error: Unable to connect to xend: Connection refused. Is xend running?

then I have to fully restart dom0. This happens every time.

I am using xen of fedora8 distribution with different clients but the problem exists in both cases using a Fedora or gentoo domU.
I post version Info at the end of the mail.

I have tried a lot of things to get hold of what causes the problem:

In domU i tried to copy data from /home (mounted via NFS) into /root.
NO PROBLEM, the error only occurs on copying into /home
dom0(NFS server) <--  domU(NFS client)  PROBLEM
dom0(NFS server)  --> domU(NFS client)  NO PROBLEM

I also tried it the other way round, but this caused no problem:
dom0(NFS client) <--  domU(NFS server)  NO PROBLEM
dom0(NFS client)  --> domU(NFS server)  NO PROBLEM

I also tried to export and mount from localhost for domU and dom0, no problem.
dom0(NFS client) <--  dom0(NFS server)  NO PROBLEM
dom0(NFS client)  --> dom0(NFS server)  NO PROBLEM

domU(NFS client) <--  domU(NFS server)  NO PROBLEM
domU(NFS client)  --> domU(NFS server)  NO PROBLEM

I configured NFS export on some other machine on the network and mounted this export as /home on my domU. There was no problem copying data of any Size in any direction.

It is not only a Problem of copying data into /home the system crashes also if I write Data into /home using cat or dd.

It is not a Problem of access rights, I do all the tests as user root, and as I wrote above the problem only occurs with writes biger then 200 kB. With less it works without any Problem.

I tried to setup the NFS export over the bridge of the external IP Address, but I also set up an only virtual device "virbr0". The Problem occurs in either cases.

I can copy data of any Size from domU to dom0 using scp or netcat.

I cannot believe it, but all the tests show, that this problem only occurs in the one special case described above. Only one direction, only on NFS.

Is this a Bug or am I doing anything obviously crazy that I have overlooked?

Thank you for your response,

Here some Version Info of the dom0 (the problem occurs independently from the domU very different domUs have been tested )

[root@dom0 ~]# /usr/sbin/xm info
release                : 2.6.21-2950.fc8xen
version                : #1 SMP Tue Oct 23 12:24:34 EDT 2007
machine                : i686
nr_cpus                : 2
nr_nodes               : 1
sockets_per_node       : 1
cores_per_socket       : 2
threads_per_core       : 1
cpu_mhz                : 1862
hw_caps : bfebfbff:20100000:00000000:00000140:0000e3bd:00000000:00000001
total_memory           : 2046
free_memory            : 126
xen_major              : 3
xen_minor              : 1
xen_extra              : .0-rc7-2950.fc8
xen_caps               : xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p
xen_scheduler          : credit
xen_pagesize           : 4096
platform_params        : virt_start=0xf5800000
xen_changeset          : unavailable
cc_compiler            : gcc version 4.1.2 20070925 (Red Hat 4.1.2-32)
cc_compile_by          : kojibuilder
cc_compile_domain      : (none)
cc_compile_date        : Tue Oct 23 12:22:00 EDT 2007
xend_config_format     : 4

Xen-users mailing list

<Prev in Thread] Current Thread [Next in Thread>