Re: [Xen-users] Cheap IOMMU hardware and ECC support importance

[Adam Goryachev <mailinglists@xxxxxxxxxxxxxxxxxxxxxx>]

On 30/06/14 20:06, Gordan Bobic wrote:
> On 06/29/2014 08:12 AM, lee wrote:
> > Gordan Bobic <gordan@xxxxxxxxxx> writes:
> >
> > > > On 06/28/2014 08:45 AM, lee wrote:
> > > > [...]
> > > >
> > > > I am not a fan of virtualization for most workloads, but sometimes
> > > > it is convenient, not least in order to work around deficiencies of
> > > > other OS-es you might want to run. For example, I don't want to
> > > > maintain 3 separate systems - partitioning up one big system is
> > > > much more convenient. And I can run Windows gaming VMs while
> > > > still having the advantages of easy full system rollbacks by
> > > > having my domU disks backed by ZFS volumes. It's not for HPC
> > > > workloads, but for some things it is the least unsuitable solution.
> > > >
> > > > Not even for most?  It seems as if everyone is using it quite a lot,
> > > > make it sense or not.
> > > Most people haven't realized yet that the king's clothes are not
> > > suitable for every occasion, so to speak. In terms of the hype cycle,
> > > different users are at different stages. Many are still around the
> > > point of "peak of inflated expectations". Those that do the testing
> > > for their particular high performance workloads they were hoping to
> > > virtualize hit the "trough of disilusionment" pretty quickly most of
> > > the time.
> > Why would they think that virtualization benefits things that require
> > high performance?
> I don't. But many people think it makes negligible difference because 
> they never did their testing properly.
> > When I need the most/best performance possible, it's
> > obviously counter productive.
> Apparently it's not obvious to many, many people.
Virtualisation also lends itself nicely to helping improve uptime. ie, 
physical hardware failure of the dom0 will crash the domU's, but you can 
restart the domU's on another dom0 (as long as you use a SAN, or 
replicated storage/etc).
I also noticed a lot of talk about remus some time ago, and thought it 
looked really promising. Having a quick look at 
http://wiki.xen.org/wiki/Remus shows that it is still getting better. 
When that arrives, you won't have any downtime due to dom0 failure 
(though I guess you need to double the resources).
PS, this is my personal advantage of using virtualisation... If I need n 
servers to run all my VM's, then with n+1 I can survive a failure of a 
dom0 (albeit with a reboot of the VM's being run there at the time). I 
still get to save on overall hardware requirements, as well as being 
able to live migrate for scheduled hardware maintenance/etc.
Regards,
Adam
--
Adam Goryachev Website Managers www.websitemanagers.com.au

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