I work in the saas world and was looking around for a personal dedicated vps which then sparked my intrest quite a bit. I notice alot of the vps providers were using vertuozzo an OS Level Virt. Upon reviewing what vertiouzzo is I started thinking why not bring OS Virtialization(Virtuozzo) together with HW Virtualization(ESX). It was/is hard to find any data on this topic.

I tried to get a licesce for the eval of Virtuozzo containers but it requires a phone call with sales to obtain. So the below is pending full review of the product and is based on facts gathered and my persional opinion, all clarification and comments are welcomed.


Pros:
Environment Consistency
Environment elasticity
Common configurations can be set once and carry over to the additional containers.
MS DTC Port Ranges
Alteris
Symantec

Application install can be done once and then pointed to another Site Server via script/registry modification.
The major OS components are loaded once and shared by the containers
More threads processing for higher availability (.net 1.2 gig limitation per app pool)
Point in time recovery at container and Guest level.
Copying one vmguest to another host would bring over multiple machines of that type and could aid in DR situations

Cons:
If guest server needs to be rebooted it will reboot all of the containers originating with that guest. 1 core OS failure will affect many threads(containers/applications)
Higher density has higher risk

Thoughts:
Speaks to standards and threading.
New Server(conatiner)deployment can be completed in moments and configured via scripting.
Reuse of one Core OS should greatly reduce the overhead that 16 to 24 VMguests would utilize.
I wonder how updating applications on the virtuozzo host will impact the containers
Or will it be better to just replace the virtuozzo hosts with new ones containing the new versions of the applications.
How well will the containers interact with snmp monitoring and counters(such as orion)


Ill update this thread with my experience once im able to get that license. Thanks in advanced for any thoughts/facts/statistics.

I've ran OpenVZ in Xen (long story why I did it) but as long as your running one HW virtualized container (the Xen) in order to maintain some form of HA, you really wont notice any issues.

Also anyone who tells you that Virtuozzo is is not as powerful as Xen, or if someone ties to post that Virtuozzo isn't true virtualiation because it doesn't give you swap is misleading you with non-fact.