Using Ubuntu 64 bit server

Christopher Chan christopher.chan at
Thu Oct 21 01:33:08 UTC 2010

On Thursday, October 21, 2010 03:03 AM, Larry Alkoff wrote:

>> Why Larry? Just curious.
> I ask about Kubuntu desktop 32 or 64 bit version for 2 reasons:
>     1.  I know that there used to be a speed degradation problem caused
> by "thunking" needed to convert 64 bit system calls into 32 bit for
> those OS that needed it.  I'm still trying to find out if Ubuntu
> "thunks" and whether it is still a problem.
>     2.  I run other Kubuntu 32 bit desktops.  They are my 'production'
> systems that are in daily use.  They all use rsync to both to keep the
> data the same and backed up.  My concern is that there will be
> differences in the data caused by the different 32/64 bit systems and
> I'd prefer not to have those kind of complications.  Also not all of my
> computers will support 64 bits so I'd rather stick with the 32 bit
> systems for a while.

There will be no differences in data on disk as the filesystem stores 
data differently from whatever mode the kernel is running in, whether 
32-bit or 64-bit. Eg: A mysql isam database would have no trouble being 
read whatever the actual platform so long as the cpu uses the same 
endianness. That is, it does not matter whether it is 32/64bit Linux, 
FreeBSD, Windows, Solaris, whatever, if it is on x86/x64, it will work. 
Filesystems then to share the same characteristics with data stored on 
them although there might be differences in maximum possible sizes 
depending on the filesystem and the mode the kernel is running in.

>>>> Windows XP
>>>> Windows 7
>> there a paravirtualized graphic driver for Windows under KVM
>> available yet? No? Ah shucks.
> Darn

I take that back. You can use the VMWare driver for versions of qemu 
above 0.9.x or even 0.9.1 IIRC as Jordon pointed out. Since you are 
running Lucid, you should be fine.

>>>> Apple OS X (possibly)
>> /me stares. Let us know if you get that working Larry. :-D
> I'll let you know.
> But first I have to get Kubuntu working virtualized.  Know any good
> sources of info?

The steps for any operating system will be pretty much the same if you 
use CD/DVD iso files for installation.

>> 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.
> My instinct is to try KVM first since it's a part of Ubuntu and the kernel.

Oh yes, going for a native solution that is stable is most probably best.

> I'm not sure of the difference between hardware virtualization vs
> paravirtualization unless para refers to software.
> I'm new to this but since I have just gotten the server working it's
> time to learn all about virtualization.

I guess Jordon has a point about 'hardware assisted'. KVM is a full 
virtualization solution that makes use of hardware virtualization 
technology available to achieve near native performance in certain 
areas. Full virtualization means that the guest operating system can be 
installed as is without any special modifications to it to make it run 

>> 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.
> I read about vertio (actually virtfs) in Linux Pro Journal (Sept 2010)
> but there was a comment in the article that a maintainer has not yet
> been found for (K)ubuntu which I take means KVM.

virtio is not virtfs. Not read that issue or any issues of the Linux Pro 
Journal but a quick look at the first few entries in Google about virtfs 
show that virtfs can mean many things and none of them have anything to 
do with virtio. The closest relationship here is with kvm for sharing 
files between the host and guest operating systems.

virtio is a Linux framework for providing network and storage i/o 
drivers in virtualized operating systems that will access these 
resources on the host directly and so not incurring the big penalties if 
you emulated then for the guest operating systems. Basically 
paravirtualization of network and storage.

You will need to do some tricks to get virtio working on XP (yes! there 
is finally a virtio driver for XP! I guess it might really be bye bye 
vbox on Linux for hosting XP guests)

> Again, I'm new to virtualization (but not Linux) so I'm looking for all
> the info available.

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