Centos 5.4 x86_64 Guest 4GB RAM Breaks paravirt network

[s34gull]

Greeting fellow VritualBox users!

I have several Centos 5.4 x86_64 Guests running in VirtualBox 3.1.6. uname reports identical kernels across all three VMs; each guest has 2CPUs assigned.

Code: Select all

uname -a 
Linux uscobrmfa-gg-50 2.6.18-164.15.1.el5 #1 SMP Wed Mar 17 11:30:06 EDT 2010 x86_64 x86_64 x86_64 GNU/Linux

Prior to today, I was running each of these guests with <= 2GB RAM. In this configuration paravirtualized network drivers were working properly for one DHCP guest and the other two Static-IP guests.

Today I needed to run several tests which required assigning additional RAM to each of these VMs, so i upped the allocated RAM to 4096MB on each. On reboot, none of the VMs would connect to the network properly. The interfaces would come up (ifup) but no packets were flowing out-from (ssh, ping, nslookup) or in-to (ssh, ping) the guests. I had to shutdown the VMs again and reconfigure them to use the Intel PRO/100 T Server (82543GC), whereupon the Guest networking returned to its nominal state. Has anyone else run into issues with paravirtualized networking and large RAM allocations?

[joatca]

Yes, I can confirm this behaviour on a CentOS 5.4 guest (4-CPU). I've found that it will work OK at 3.5G but close to 4G it stops working exactly as you describe... interface appears to come up OK, but no traffic flows.

The only VM I have that needs 4G is a CentOS one. I have a couple of Ubuntu VMs too, I plan to bump one of them to 4G at some point to see if they do the same thing. However, I've had other showstopper problems with this CentOS VM that I'm still diagnosing which will be the subject of a future post, so I may not get a chance to try the 4G/Ubuntu thing for a few days.

[Technologov]

Hmmm... worth opening a bug.

Plus drop link here.

[fixedwheel]

VBox or virtio-net bug?

Debian Lenny 64bit guest: virtio-net working w/ up to 3584MB, not working w/ 3712MB and more
Debian Lenny 64bit host, VBox PUEL 3.2.0

[Technologov]

IIRC this works on Qemu/KVM. But worth to recheck this on Qemu/KVM.
So probably a VBox bug.

[Technologov]

update: just tested on RHEL 5, x64 host.

Host: AMD Opteron, 24 CPU + 48 GB RAM, RHEL 5.X, x64, kvm-83-154.el5, VBOX 3..2..0
Guest; RHEL 5.4, x64 + VirtIO

qemu/kvm works with 16 GB RAM + virtIO.
VirtualBox fails.

Opened bug:
http://www.virtualbox.org/ticket/6784

feel free to add data...