Matthieu PATOU
2005-Dec-11 20:24 UTC
[Xen-users] high ? number of dropped packet on xen vif
Hello all, it seems i''m facing a problem with xen networking. I have some hang up with my NFS server running in domU. I noticed that when i got a hang up i also see an increase of the number of dropped packet of the vif interface. it seems that dom0 has some trouble with sending the packet to the domU Currently the rate of dropped packet (the TX ones ) is 10% of the total transmited. I try to increase dom0 memory but i doesn''t seems to have an effect on the rate of dropped packet. Is there some one who has also faced this problem ? Do you have an idea of what can i try to solve the problem ? regards Ps: My box is a PIII 600 Mhz with 384Mo RAM _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Ian Pratt
2005-Dec-11 22:09 UTC
RE: [Xen-users] high ? number of dropped packet on xen vif
> Hello all, > it seems i''m facing a problem with xen networking. > I have some hang up with my NFS server running in domU. > I noticed that when i got a hang up i also see an increase of > the number of dropped packet of the vif interface.Which version of Xen are you running here, 3.0.0? Is this a soft hang that later recovers?> it seems that dom0 has some trouble with sending the packet > to the domU Currently the rate of dropped packet (the TX ones > ) is 10% of the total transmited.Which counters are you referring to here? The TX fields of the vifX.0 interface?> I try to increase dom0 memory but i doesn''t seems to have an > effect on the rate of dropped packet. > Is there some one who has also faced this problem ? > Do you have an idea of what can i try to solve the problem ?If you built from source, please modify xen/Rules.mk to turn on debug=y and then rebuild. Thanks, Ian _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Matthieu PATOU
2005-Dec-12 22:46 UTC
Re: [Xen-users] high ? number of dropped packet on xen vif
On Sun, 11 Dec 2005 22:09:53 -0000 "Ian Pratt" <m+Ian.Pratt@cl.cam.ac.uk> wrote:> > > Hello all, > > it seems i''m facing a problem with xen networking. > > I have some hang up with my NFS server running in domU. > > I noticed that when i got a hang up i also see an increase of > > the number of dropped packet of the vif interface. > > Which version of Xen are you running here, 3.0.0? >No a xen unstable 2.0 with a changeset around 2.0.6 I''ll do an upgrade to 2.0.7> Is this a soft hang that later recovers? >Yes my NFS is mounted with a soft option, to reproduce everytime the problem i copy a 3 Mo or more from /usr/local which is on the harddrive of the client to a directory of the NFS volume. Meanwhile i monitor the network on the client, on dom0 and in domU (the NFS server) i retransmission of frame from the client to the server and also ICMP frame from the server to the client indicating that some packet have been already received. Again i''m wondering if some one has already done this setup (putting a NFS server in a DOMU) if so what are the results ?> > it seems that dom0 has some trouble with sending the packet > > to the domU Currently the rate of dropped packet (the TX ones > > ) is 10% of the total transmited. > > Which counters are you referring to here? The TX fields of the vifX.0 > interface?Yes ifconfig vif2.0 for instance> > > I try to increase dom0 memory but i doesn''t seems to have an > > effect on the rate of dropped packet. > > Is there some one who has also faced this problem ? > > Do you have an idea of what can i try to solve the problem ? > > If you built from source, please modify xen/Rules.mk to turn on debug=y > and then rebuild. >I''ll do an upgrade soon to the latest 2.0.7 or do you prefer that i do a big update to Xen 3.0 ?> Thanks, > Ian >Regards Matthieu _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Matthieu PATOU
2005-Dec-12 22:46 UTC
Re: [Xen-users] high ? number of dropped packet on xen vif
On Sun, 11 Dec 2005 22:09:53 -0000 "Ian Pratt" <m+Ian.Pratt@cl.cam.ac.uk> wrote:> > > Hello all, > > it seems i''m facing a problem with xen networking. > > I have some hang up with my NFS server running in domU. > > I noticed that when i got a hang up i also see an increase of > > the number of dropped packet of the vif interface. > > Which version of Xen are you running here, 3.0.0? >No a xen unstable 2.0 with a changeset around 2.0.6 I''ll do an upgrade to 2.0.7> Is this a soft hang that later recovers? >Yes my NFS is mounted with a soft option, to reproduce everytime the problem i copy a 3 Mo or more from /usr/local which is on the harddrive of the client to a directory of the NFS volume. Meanwhile i monitor the network on the client, on dom0 and in domU (the NFS server) i retransmission of frame from the client to the server and also ICMP frame from the server to the client indicating that some packet have been already received. Again i''m wondering if some one has already done this setup (putting a NFS server in a DOMU) if so what are the results ?> > it seems that dom0 has some trouble with sending the packet > > to the domU Currently the rate of dropped packet (the TX ones > > ) is 10% of the total transmited. > > Which counters are you referring to here? The TX fields of the vifX.0 > interface?Yes ifconfig vif2.0 for instance> > > I try to increase dom0 memory but i doesn''t seems to have an > > effect on the rate of dropped packet. > > Is there some one who has also faced this problem ? > > Do you have an idea of what can i try to solve the problem ? > > If you built from source, please modify xen/Rules.mk to turn on debug=y > and then rebuild. >I''ll do an upgrade soon to the latest 2.0.7 or do you prefer that i do a big update to Xen 3.0 ?> Thanks, > Ian >Regards Matthieu _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Matthieu PATOU
2005-Dec-27 22:21 UTC
Re: [Xen-users] high ? number of dropped packet on xen vif
Hello i did some test with xen 2.0.6 and xen 3.0.0 The test done with xen 2.0.6 is switching from UDP to TCP and it works great the transfert speed has increased. And of course, with the nature of TCP (in term of network sessions) there is no more timeout and hangs. I''ve also installed a box with ubuntu 5.10 as Dom0 and Debian sarge as domU. On this box with a bridged configuration there is no communication between the client (a standalone linux box running ubuntu 5.04) and the server when i try to copy a big file (1 Mo or more). It appears that fragmented packet (or at least packet with 5 or more fragment) didn''t cross the bridge and so the server and so the client keeps on trying to send the first bytes of the file and fail because there is no return not even a failure but small file are OK (if the try is done before the test of the big file). I''ve also done a test with a different setup on the Xen 3.0 box, i''ve setup dom0 as a router between the domU serving nfs file and the client. In this configuration i haven''t got hang and the time needed to copy the file is less than the original configuration (xen 2.0.6 + bridging) but when i start ethereal i still see some packet retransmission and i think it''s not normal because the client and xen server are on the same switch with good cable and only a couple of meter away. Any idea of why there is this huge problem with the bridge and why there is still packet loss (or not acknoledge quickly enougth) ? Regards Matthieu> > >>Hello all, >>it seems i''m facing a problem with xen networking. >>I have some hang up with my NFS server running in domU. >>I noticed that when i got a hang up i also see an increase of >>the number of dropped packet of the vif interface. > > > Which version of Xen are you running here, 3.0.0? >> Is this a soft hang that later recovers? > > >>it seems that dom0 has some trouble with sending the packet >>to the domU Currently the rate of dropped packet (the TX ones >>) is 10% of the total transmited. > > > Which counters are you referring to here? The TX fields of the vifX.0 > interface? > > >>I try to increase dom0 memory but i doesn''t seems to have an >>effect on the rate of dropped packet. >>Is there some one who has also faced this problem ? >>Do you have an idea of what can i try to solve the problem ? > > > If you built from source, please modify xen/Rules.mk to turn on debug=y > and then rebuild. > > Thanks, > Ian > > > !DSPAM:439ca3c8175661804284693! > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users