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Re: [Xen-users] The death of XEN by Novell

You're definitely right Tao,

you should take a look at datacore's HA products for SAN e.g. SAN melody,
and if you want to virtualize this mission critical servers use Xen with Everrun or VMI3 for HA.

With this combo you have enterprise ready great speed and HA!


Tao Shen schrieb:
First of all, your boss should fire you for saying "windows 2008 sql server runs perfectly unless windows crashes"

Secondly, whoever delivered the xen solution on your 200k per day production server should be fired for not understanding the concept of single point of failure.

Now that you learned the lesson at 5k per hour,you should dump virtual machines and have redundant physical machines for mission critical services on your network. For 200k a day, that is 72million a year revenue, you should have a budget of at least 5 to 7 mil to handle redundancy issues, which means double or even triple redundancy networks and San storage for database servers.

Lastly, I think that either your boss bluffed you with 5k per hour cost of downtime, or you did, since I cannot imagine such incompetent people running a business valued at 15 times earning or hundreds of millions if your 72 million revenue figure is indeed correct.

Btw, xen is maintained by citrix, not Novell.

On Jul 20, 2008, at 11:36 AM, "Venefax" <venefax@xxxxxxxxx> wrote:

SQL Server only runs in Windows. I am now actually learning DB2 in order to
use a Linux-based database. But of course I am not dumb to put my entire
business on a database I cannot support, yet, the way I do with SQL Server.
And the beauty is the with XEN-Windows 2008, SQL Server runs perfectly,
unless Windows crashes.

-----Original Message-----
From: Florian Manschwetus [mailto:florianmanschwetus@xxxxxx]
Sent: Sunday, July 20, 2008 12:30 PM
To: Mark Williamson
Cc: xen-users@xxxxxxxxxxxxxxxxxxx; Venefax; jim burns
Subject: Re: [Xen-users] The death of XEN by Novell

Mark Williamson schrieb:
On Sunday 20 July 2008, jim burns wrote:
On Sun July 20 2008 9:51:52 am Venefax wrote:
The Novell engineer showed me a technical document, which I did not
the number, on the Novell web site, where it said: windows SMP using the
Novell driver crashes.
That's what I thought - the problem is with Novell's PV drivers, not Xen.
James had some initial problems with SMP also.

Right, that's important.  Novell's PV drivers are their code so those
might have limitations that plain Xen does not.  Presumably it would be
possible to run using fully emulated IO instead of PV drivers but I
this could have performance problems in your configuration.  Could be
worth a
try, if you can afford to experiment.

If the Windows VMs themselves are crashing due to Novell's PV drivers then
afraid this limitation / problem is really Novell's responsibility and
would be the best people to approach for assistance / complaints.  The
for those drivers isn't open, so only Novell can fix them. If the Novell
drivers are somehow crashing your Linux domains or dom0 or Xen itself then

that might be a Xen bug and it would be useful to post more details here.

For comparison, Citrix/XenSource supply with their product PV drivers for
Windows that are - AFAIK - a different codebase and may not have these
limitations.  So do Virtual Iron, for their Xen-based product.  Both of
can only be used with their respective commercial hypervisors, AFAIK.
Harper's PV drivers for Windows are GPL but still under development and so
doubt they'd be recommended for heavy production use.

There are a lot of different PV driver solutions for Windows about and
none of
them are officially part of the OSS Xen project; only one of them is even
Open Source.

I really wonder why you run your SQL servers in windows and all the rest
in Linux???
I asume especially for databases is Windows a bad base, but i have a
win20008 sharepoint running on xen 3.2.1 with 2 vcpus it works great and
stable with james drives.
And if you like to use this single Box, you may ask SUN (Solaris and


I use a SIP Server on the Linux side, talking hundreds of times per
second to SQL Server, so I need SMP 8 ways on both  ends.
Something I've never seen you actually say is that you *tried* vcpu=1,
the performance was bad. So far, it sounds like theory to me. Even with 1
vcpu, playing with scheduling weights should help.

Venefax, are you able to try this?

Thank you,

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