progressdll
2007-Oct-10 07:11 UTC
[Fedora-xen] are dropped packets a sign of network problem?
in a xen environment , i see a lot op dropped packets via netstat -i Is this a sign of network problems, or is it normal to see this kind of numbers? i''m not sure how to interprete the data. is this normal, bad, critical. What are your stats on this? I guess i have a xen issue of some sort, but not sure what yet # netstat -i Kernel Interface table Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg eth0 1500 0 53999491 0 0 0 6234874 0 0 0 BMRU lo 16436 0 9247734 0 0 0 9247734 0 0 0 LRU peth0 1500 0 135679270 0 0 0 95455766 0 0 0 BORU tap0 1500 0 5411876 0 0 0 35071803 0 0 0 BMRU vif-vmdeb 1500 0 0 0 0 0 35 0 333350 0 BORU vif0.0 1500 0 6234874 0 0 0 53999492 0 0 0 BORU vif6.0 1500 0 55813641 0 0 0 98482968 0 482338 0 BORU vif6.1 1500 0 0 0 0 0 39 0 46875771 0 BORU vif68.0 1500 0 0 0 0 0 0 0 0 0 BOU vif69.0 1500 0 9349348 0 0 0 30571290 0 3282 0 BORU vif69.1 1500 0 0 0 0 0 44 0 18947590 0 BORU vif70.0 1500 0 129605 0 0 0 460256 0 702 0 BORU vif70.1 1500 0 0 0 0 0 35 0 333350 0 BORU xenbr0 1500 0 46298695 0 0 0 0 0 0 0 BORU -- View this message in context: http://www.nabble.com/are-dropped-packets-a-sign-of-network-problem--tf4598987.html#a13130626 Sent from the Fedora Xen mailing list archive at Nabble.com.
Gabriel M. Schuyler
2007-Oct-12 17:35 UTC
Re: [Fedora-xen] are dropped packets a sign of network problem?
We''ve had some network problems that were resolved by disabling tcp checksum offloading on all the domUs. Our symptom was we couldn''t ssh (or do much else) between two domUs on the same physical host. So on each domU we run: sudo /sbin/ethtool -K eth0 tx off Hope this helps! Gabe -- Gabriel M. Schuyler, sysop Intercasting Corporation On Oct 10, 2007, at 12:11 AM, progressdll wrote:> > in a xen environment , i see a lot op dropped packets via netstat -i > > Is this a sign of network problems, or is it normal to see this > kind of > numbers? i''m not sure how to interprete the data. is this normal, bad, > critical. What are your stats on this? > > I guess i have a xen issue of some sort, but not sure what yet > > # netstat -i > Kernel Interface table > Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR > TX-DRP > TX-OVR Flg > eth0 1500 0 53999491 0 0 0 6234874 > 0 0 > 0 BMRU > lo 16436 0 9247734 0 0 0 9247734 > 0 0 > 0 LRU > peth0 1500 0 135679270 0 0 0 95455766 > 0 0 > 0 BORU > tap0 1500 0 5411876 0 0 0 35071803 > 0 0 > 0 BMRU > vif-vmdeb 1500 0 0 0 0 0 35 0 > 333350 > 0 BORU > vif0.0 1500 0 6234874 0 0 0 53999492 > 0 0 > 0 BORU > vif6.0 1500 0 55813641 0 0 0 98482968 0 > 482338 > 0 BORU > vif6.1 1500 0 0 0 0 0 39 0 > 46875771 > 0 BORU > vif68.0 1500 0 0 0 0 0 0 > 0 0 > 0 BOU > vif69.0 1500 0 9349348 0 0 0 30571290 0 > 3282 > 0 BORU > vif69.1 1500 0 0 0 0 0 44 0 > 18947590 > 0 BORU > vif70.0 1500 0 129605 0 0 0 460256 > 0 702 > 0 BORU > vif70.1 1500 0 0 0 0 0 35 0 > 333350 > 0 BORU > xenbr0 1500 0 46298695 0 0 0 0 > 0 0 > 0 BORU > > -- > View this message in context: http://www.nabble.com/are-dropped- > packets-a-sign-of-network-problem--tf4598987.html#a13130626 > Sent from the Fedora Xen mailing list archive at Nabble.com. > > -- > Fedora-xen mailing list > Fedora-xen@redhat.com > https://www.redhat.com/mailman/listinfo/fedora-xen
Daniel P. Berrange
2007-Oct-12 17:44 UTC
Re: [Fedora-xen] are dropped packets a sign of network problem?
On Fri, Oct 12, 2007 at 10:35:25AM -0700, Gabriel M. Schuyler wrote:> We''ve had some network problems that were resolved by disabling tcp > checksum offloading on all the domUs. Our symptom was we couldn''t > ssh (or do much else) between two domUs on the same physical host.That should be neccessary at all - there were some bugs in this respect a long time ago, but it works fine now, assuming you keep your kernels up2date with errata. Turning off checksum offload will destroy network performance/throughput for your guests - particularly guest<->guest networking, but also guest -> network. Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|