Gentoo VM Networking is intermittant

[Lawbayly]

I've currently got a Gentoo VM connected to the internet using Bridged networking and the Virtio networking device, and it works just fine for a while but then it completely dies, to the extent that I can't ping the host I'm running on and no longer can get dhcp anymore

If I leave it for about 10 minutes after the network dies, it will eventually come back up.

I've attached the log files, I'll also try this on another OS to see if I can get the same issue

Thanks,

[frank]

Well, that sounds more like a virtio-net problem, not a general networking problem. That device is still quite new and not enough tested.

[Aleksey Ilyushin]

I installed Gentoo guest (from install-x86-minimal-20091103.iso), enabled virtio support and did some network stess testing (wget, iperf). I encountered no issues.

Can you take a look at what is happening with traffic on host's interface with tcpdump when network is dead? You can also enable internal network tracing with 'VBoxManage modifyvm <name> --nictrace<adapter_number> on'.

[Lawbayly]

I did a nictrace of the VM and I was able to get the network to crash again (seems to happen alot while downloading the stage3)

I wasn't able to get a tcpdump in time (didn't have the package installed) but I got a wireshark capture instead, but it just shows nothing, until the network comes alive, hope it's useful

Unfortunately I'm unable to attach the nictrace to this forum as it seems to be too big (137.2MB), I've had a look at it and I do think there is something wierd going on, I'll post a screenshot of where it goes wrong

[Lawbayly]

I've snipped up the capture using wireshark to show just the piece where the network fails, Hope it helps,

I'm going to upgrade to Beta 3 to see if that helps,

Thanks,

[Lawbayly]

Networking is still intermittant in Beta3,

Thanks,

[Lawbayly]

after a while of disconnects and reconnects, ping now comes up with the error

ping: sendmsg: No buffer space avaliable

I'm trying to get the same problem to happen in a debian VM but no dice, It works just fine in debian, even while the gentoo is failing miserably

Maybe it's a gentoo problem? Wait..... My machine froze up, while the gentoo VM was running, KDE's panel completely stopped responding to commands and the VM's also stopped responding to commands, RAM and CPU Usage was fine during the freeze, I paused the gentoo VM and everything sprang back to life, something is very wrong!

[Aleksey Ilyushin]

The only thing I was able to make out of the logs is that you probably have IP forwarding enabled on your host. This causes duplicate packets since vbox "sniffs" a packet from host's physical interface and then the host forwards the packet to the guest causing a duplicate. This shouldn't cause any network problems though.

Does your Gentoo guest runs from runs from install CD or you have installed it to the hard drive? The reason I am asking is that I want to know if you run a stock kernel or you've configured the one yourself. If the guest boots from HD, do you have Gnome and network manager installed? I saw a recent bug report with similar symptoms on bugs.gentoo.org.

[Lawbayly]

I was initally installing it from the install cd you mentioned earlier "install-x86-minimal-20091103.iso" I got to downloading the stage3 file from http://ftp.swin.edu.au/gentoo/ Which actually is pretty slow, ran for about 5 minutes just fine, then suddenly cuts dead, at around 75%, where I cannot ping anywhere, I didn't see any activity on the host side of the interface until it suddenly cuts back in, where I recieve loads of arp requests and pings, which were sent earlier.

I've actually installed the kernel now and gone to the inital install (still just bash) and it still cuts dead at times, even more so now, I found that downloading something and making pings at the same time kills it faster.

I have no GUI as of yet, so it's nothing to do with gnome.

I have a hunch it might be something to do with 2xCPU's being configured, verified, I've managed to make debian VM do the same thing by configuring 2xCPU's then downloading a big 1GB Video file off a webserver using links.

So I think once this gentoo has finished compiling, I'll switch back the VirtIO adapter then try it with 1CPU and see if I can get it to crash again

Try it with two virtual CPU's configured in VirtualBox, then try putting load on the adapter, and maybe the CPU as well (It runs very intermittant while downloading and compiling at the same time I've realised)

[Aleksey Ilyushin]

Thanks for the hint! Indeed I had only one CPU configured in my guest. I was able to reproduce the problem easily with 2 CPUs enabled. I'll keep you posted on the progress.

[Lawbayly]

Thanks for that, I'll be happy to test the solution when it arrives