Re: NIC limit

[linux_kvm@proinbox.com]

>The PCI bus has only 32 slots (devices), 3 taken by chipset + vga, and
>a 4th if you have, for example, a virtio disk.  Are you sure these are
>33 PCI devices and not 33 PCI functions?

No, not sure.
Apparently my statement was based on an uninformed assumption.

I tested using a VM that had 30 (removable-per-web-interface)
attachments, and added 3x IDE HDDs to bring it above what I thought was
32 devices:
28 virtio NICs
 1 IDE CD-ROM
 1 virtio HDD
+3 IDE HDDs

I could add IDE up past 32 and it would start, as soon as there were
more than 28 NICs with or without the 3 IDE HDDs, start would fail.


On Wed, 06 Oct 2010 10:18 -0700, "Chris Wright" <chrisw@sous-sol.org>
wrote:
> * linux_kvm@proinbox.com (linux_kvm@proinbox.com) wrote:
> > Hi again everybody,
> >  
> > One of the admins at the ProxmoxVE project was gracious enough to
> > quickly release a package including the previously discussed change to
> > allow up to 32 NICs in qemu.
> 
> You mean they patched qemu to increase the MAX_NICS constant?  Nice to
> get the quick turn around.
> 
> Te better choice is to use a newer command line.  Not only does it avoid
> the MAX_NICS limitation, but it also enables standard virtio-net offload
> accelerations.
> 
> > For future reference the .deb is here:
> > ftp://download.proxmox.com/debian/dists/lenny/pvetest/binary-amd64/pve-qemu-kvm_0.12.5-2_amd64.deb
> >  
> > Upon creating & running the VM with the newly patched qemu-kvm app
> > installed, I found a NIC limitation remained in place, presumably
> > imposed by some other aspect of the environment.
> >  
> > The machine would start when it had 33 PCI devices, as long as no more
> > than 28 of them were NICs.
> 
> The PCI bus has only 32 slots (devices), 3 taken by chipset + vga, and
> a 4th if you have, for example, a virtio disk.  Are you sure these are
> 33 PCI devices and not 33 PCI functions?
> 
> thanks,
> -chris
>