[THIN] Re: VMWare
- From: "Carl Stalhood" <cstalhood@xxxxxxxxxxxxx>
- To: <thin@xxxxxxxxxxxxx>
- Date: Sun, 30 Oct 2005 21:10:42 -0600
There are actually two kernels running on an ESX server with the hardware
divided between them. The Linux kernel gets
some CPU resources, 256 MB RAM (administrator defined), 1 SCSI controller, and
one NIC. The VMkernel gets everything
else. When you configure the Startup Config in the ESX MUI, you are essentially
dividing the hardware between the two
kernels.
The Linux kernel is responsible for administration and bootstrapping the
VMkernel. It is similar to DOS on a NetWare
server. The Linux kernel starts first and then it starts the VMkernel.
The administration website runs on the Linux kernel. All of the VMs run on the
VMkernel. The VMkernel was written from
scratch and is very small (couple hundred thousand lines of code, I think).
The VMkernel is designed to allow the virtual machines almost direct access to
the hardware for CPU and Memory (SCSI and
NIC are emulated). CPU access by the virtual machines is scheduled by the
VMkernel, not the Linux kernel.
_____
From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of
Jeff Pitsch
Sent: Sunday, October 30, 2005 8:11 PM
To: thin@xxxxxxxxxxxxx
Subject: [THIN] Re: VMWare
ESX does equal linux because if it wasn't for the fact that they could hook
deeper into the kernel (or whatever) the
performance difference between GSX and ESX would be almost nothing. Now you
could argue that any open source OS would
accomplish the same thing but they chose linux. The VM engine goes through
linux to access the hardware. Now I admit,
I may be completely wrong but that's how it's been explained to me by VMWare
and others. I just can't see anyone
recreating the wheel (OS). Otherwise, they would have done exaclty the same
thing with GSX.
Jeff
On 10/28/05, Chris Fraser <chrisfraser@xxxxxxxxxx> wrote:
Ya sure but the fact is that ESX does not use the Linux kernel as it's
virtualization engine. ESX != Linux. It uses a modified Linux VM for the
management interface. Simple as that.
If it wasn't for the Apple II or TRS 80 or Commodore 64 or whatever then
none of this would be possible :)
Jeff Pitsch wrote:
> If it wasn't for the linux kernel then none of it would be possible.
>
> On 10/28/05, *Chris Fraser* <chrisfraser@xxxxxxxxxx
> <mailto:chrisfraser@xxxxxxxxxx>> wrote:
>
> ESX will always have better performance because the VMkernel (not linux
> kernel) has full control to manage all hardware resources and doesn't
> have to pass request through an OS layer (like GSX).
>
> Single proc is definitely the way to go on almost all VMs. I'm still
> puzzled at the reasoning behind announcing 4-way SMP, esp since it will
> benefit maybe %1 of VMs.
>
> Best Practices Using VMware Virtual SMP
> http://www.vmware.com/pdf/vsmp_best_practices.pdf
>
> ESX Server Architecture and Performance Implications
> http://www.vmware.com/pdf/esx2_performance_implications.pdf
>
> ESX Performance Tips and Tricks
> http://www.vmware.com/pdf/esx_performance_tips_tricks.pdf
>
> Reference & Planning for Virtualizing Citrix
> http://www.vmware.com/pdf/esx_citrix.pdf
>
> Reference and Capacity Planning with Citrix Presentation Server (for ESX
> Server 2)
> http://www.vmware.com/pdf/esx2_citrix_planning.pdf
>
>
>
> Jeff Pitsch wrote:
> > ESX will always have better performance than GSX because ESX is tied
> > more closesly to the linux kernel. GSX is strictly a service and
> > doesn't tie deeply into the OS at all.
> >
> > Jeff
> >
> >
> > On 10/28/05, *Jon D* <rekcahpmip@xxxxxxxxx
> <mailto:rekcahpmip@xxxxxxxxx>
> <mailto:rekcahpmip@xxxxxxxxx>
> > <mailto:rekcahpmip@xxxxxxxxx <mailto: rekcahpmip@xxxxxxxxx
> <mailto:rekcahpmip@xxxxxxxxx> >>> wrote:
> >
> > I run citrix in VMware GSX, and I have an identical physical
> citrix
> > box. Both production.
> >
> > I wish I would have put it in ESX with SMP because the citrix box
> > can only use 1 processor which isnt good(even with GSX dual
> > processor license).
> >
> > I would say VMWare burns 20-30% of the resources(the physical can
> > probably handle 20-30% more connections).
> >
> > The performance problems I see is the physical disk, and
> mainly the
> > processor. 1 3Ghz processor is only good for maybe 23-25
> processes.
> >
> > Overall I do like it though. If my manager messes up the virtual
> > citrix server I just revert it to the last snapshot and its
> fixed.
> > If he messes up the physical one, I've got a a solid week of
> redoing
> > it ahead of me.
> >
> >
> >
> > -Jon-
> >
> >
> >
> >
> > .
> >
> >
>
> --
>
> Check out my eBay auctions
> (http://search.ebay.com/_W0QQsassZchrisfraser1111QQhtZ-1)
> and my GEMM store ( http://cfraser1111.gemm.com)
>
>
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********************************************************
This Weeks Sponsor: Cesura, Inc.
Know about Citrix end-user slowdowns before they know.
Know the probable cause, immediately.
Know it all now with this free white paper.
http://www.cesurasolutions.com/landing/WPBCForCitrix.htm?mc=WETBCC
********************************************************
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