better platform for virtualization

[Etzion Bar-Noy]

PV drivers were released by Oracle, who run their own virtualization
platform based on XenCommunity.

KVM is wasteful and requires VT support even for Linux machines. Not only
that, but its virtualized hardware is legacy old hardware supplied by QEMU.

The leading virtualization solutions currently in the market are Vmware
ESXi, which, for a single server is free and very nice (although you better
make sure your hardware is in their support matrix), Microsoft Hyper-V,
which is not Linux-friendly, if you care about it, and Citrix XenServer.

You can compare these three on the internet.

Less common, but aggressively in use (with the same performance profile) are
OracleVM, RHEL Xen platform (with Oracle PV drivers for Windows) - Xen
Community based.

On the level of the "low performance" you would find Vmware Server, and Sun
VirtualBox.

KVM was designed, and is focused on VDI - desktop virtualization, being the
focus of Kumranet in the past. RedHat cannot maintain two virtualization
platforms.

Assuming you aim at Windows virtualization, and assuming you want the
assurance of enterprise-class solution, I would recommend any of the top
three, with my favorite Citrix XenServer (check the pros and cons of each
and make your own decisions in that matter). Other solutions are not
complete, or will have near-zero support or knowledge base on the net.

To make things clear - I earn my keep by performing various system and IT
architecture-related integration operations, amongst are virtualization
design and implementations.
I have several customers with large XenServer farms, running
mission-critical, 24/7/365. The longer one has his farm running since about
March, containing about 40-50 VMs, including the company's Exchange server
(~400 users), several Oracle DB environments, MSSQL, ADS, TS and more. These
are memory-hungry applications, and the total memory allocated there
(usually memory is the immediate bottleneck, followed by disk IO
performance) is about 150GB ram, in total, with shared storage and the
entire shabang.

Other customers of mine use smaller environments, running one or two
servers, with several tenths of vms on them. They were unable to reach
anywhere near this capacity (amount of VMs, performance of every single VM)
using VMware Server, of course.

Make your own pick. I can only recommend to use the enterprise class tools,
especially if they can come for free, and/or you could buy support.

Ez

On Tue, Jan 19, 2010 at 10:11 PM, Oleg Goldshmidt <pub at goldshmidt.org>wrote:

> Jonathan Ben Avraham <yba at tkos.co.il> writes:
>
> > Hi Gilad,
> > Why do you recommend KVM over XEN? Have you fiddled with both? Are
> > there particular problems with XEN?
>
> Apart from the fact that XEN is paravirtualization technology and
> running a mission-critical Windows DomU is possible mostly in theory?
>
> Disclaimer: I have not touched Xen over a couple of years (when
> Windows guests were possible on KVM, at least in principle, and not
> possible on Xen). I checked the current docs out of curiousity and
> phrases like "PV drivers are being developed" and "you need to disable
> driver signature checking on (every!) reboot" [original emphasis]
> don't inspire much confidence.
>
> Other points Gilad made (KVM being much less intrusive and already in
> the vanilla kernel and provided by RedHat) are very much valid.
>
> To the OP: Xen is not for you. I have no first-hand experience (beyond
> a tiny bit of tinkering) with KVM. I have quite a bit of production
> experience with VMware. I am surprised that most of the postings focus
> on the VMware Server (previously known as GSX). IIRC the OP mentioned
> "crucial" servers but did *not* say $0 was a requirement. I'd go with
> ESX for mission-crtical stuff.
>
> For a serious installation I would not keep data (or system images,
> for that matter, but YMMV) on directly attached disks.
>
> --
> Oleg Goldshmidt | pub at goldshmidt.org
>
> _______________________________________________
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> Linux-il at cs.huji.ac.il
> http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
>
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