Using Ubuntu 64 bit server

Jordon Bedwell jordon at
Tue Oct 19 16:27:47 UTC 2010

On 10/18/2010 08:35 PM, Christopher Chan wrote:
> I have a server that has 16G of RAM too where I will be running multiple 
> Windows servers. Oh, the motherboard does not determine whether things 
> are 64-bit or not. The server I use has two AMD Opterons supplying 
> 24-cores in total, two SAS2 host controllers and will eventually have 36 
> disks connected (right now there are only 12, two as system disks, 10 in 
> a raidz2 array with one as a spare) and a dual-port Intel gbit nic 
> onboard and an addon 4 port intel gbit nic.

Go buy a 64GB quad X7550 or higher hypervisor.  I have more ram in my
personal workstations :P (My personal baby has 24GB of RAM right now).
I always preferred network storage though, I assume you don't experience
much possible downtime from rundown >.>

> there a paravirtualized graphic driver for Windows under KVM 
> available yet? No? Ah shucks.

Yes, there are.  They are provided by VMWare.  Also, you forget about
Hardware assisted [Native] virtualisation in this statement.

> /me stares. Let us know if you get that working Larry. :-D

People have.  I have to, using the same methods.

> KVM is stable when I tried it on Hardy...just don't expect any 
> speed/smooth video playback. Xen on the other a very intrusive 
> solution compared to KVM. Never found it stable even with Linux guests.

Subjective.  KVM is in the Kernel.  Xen and VMWare are not.  Both Xen
and VMWare were rejected from the Kernel until Xen and VMWare came
together and made Paravirt-OPS, AKA KVM.  Redhat and others were
involved in this too.  So much for "intrusive" right, since in the end
it is still Xen and VMWare ;)

On the subject of Xen being unstable, that is subjective too, stability
in Xen comes with experience and knowledge.  You can't call it unstable
when it runs the worlds 5 biggest clouds.

>>> 3.  How does the 64 bit server handle 32 bit code?
>>>         If by thunking, is there any speed degradation?

>> No idea, unfortunately...  I want to say that there is some thunking
>> that occurs, but honestly, that's too far into dark kernel magic
>> territory for me to give you a reliable answer.

This isn't elaborated enough.  You need to ultimately drill down the
type of virtualisation, out of the 3.  Full virtualisation (Parallels,
OpenVZ [Parallels still], Paravirtualisation [Paravirt-OPS, Xen,
Parallels, OpenVZ, VMWare] or Hardware assisted virtualisation [Xen,
VMWare, Paravirt-OPS].  If you are talking about running 32bit binaries
on 64bit systems, that of course needs to be elaborated too, because
Debian implements it different than Redhat.  Everything has a overhead
but it's all defined by scenario.

> KVM must have hardware virtualization available as it is hardware 
> virtualization module but it does support paravirtualize stuff like disk 
> and nic i/o via virtio.

You can also run Qemu/KVM without hardware support as well.  As stated
by Redhat: "You can still use QEMU/KVM, but the emulator will fall back
to software virtualization, which is FAR FAR slower."

> If Larry has enough throughput, virtio should help plenty. I have got 
> very decent disk performance under KVM with virtio for Windows. No 
> virtio then yes, forget it. It will crawl.

This is obviously subjective and scenario based.  Lets get some real
scenarios please, I mean some REAL scenarios.  Dude brought up SAN but
did not mention it's implementation.  You mentioned virtio would help
which was pretty irrelevant because we don't have a scneario. So can get
a real damn scenario please?

> You could at least verify all your bits of knowledge before passing them on.

So could you...

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