Following are some comments we've received from OpenVZ users.
I never looked in much detail into OpenVZ but quite honestly I have my doubts that it is completely sealed off and really doesn't suffer by any of the vulnerabilities I pointed out in my other mail.
OpenVZ is probably at a better spot than the vanilla kernel whith container virtualization, but I think they define "secure" much more losely than some folks are aware of.
I certainly have received a lot of value from using OpenVZ. One of the greatest open source values in the world!
I hope this helps their popularity. OpenVZ is an amazing, production quality lightweight virtualization technology. Used virtuozzo containers for infrastructure servers for years at my previous employer, and used openvz containers to run high traffic web sites for small businesses. It will most likely be years before lxc reaches the capabilities OpenVZ had in 2008.
We are very pleased with OpenVZ - stable and very functional. Really a 100% recommend for almost any type of infrastructures. It would be nice if RHEL7/CentOS7 support is added soon. Also seems that the recommended panel - OVZ Web Panel is not very well maintained and a bit outdated. We are using it and it is not very stable or production ready for customer usage and is slow developing. Mitkov, VPSBG.eu CEO
We’re booting 120,000 containers per day on OpenVZ, it’s okay I guess.
Bolszoje spasiba! :D
Paweł Tęcza, Bugzilla #658#c7
Thank you OpenVZ guys. You rocks!
Alex, Bugzilla #796
OpenVZ is awesome! We used it to build the entire infrastructure for WebEnabled's Instant Development Platform.
Salim Lakhani, WebEnabled
I'm curious. For the past few months, email@example.com have discovered (and fixed) an ongoing stream of obscure but serious and quite long-standing bugs.
How are you discovering these bugs?
Andrew Morton, Devel mailing list
OpenVZ, which also is vying for inclusion in the mainstream Linux kernel, would complement Xen well and has impressed me in the initial testing I've conducted.
Jason Brooks, Senior Analyst, Ziff Davis. eweek.com
I just wanted to congratulate you and the rest of the OpenVZ team for your excellent, excellent work. We are now have an OpenVZ subject in our 120 hours Total Linux course here at the Bluepoint Foundation, and our students really appreciate the work you've done. I'm learning a lot from lurking in the devel list too. Thanks again and keep 'em coming! :D
Engels Antonio, Bluepoint Foundation
I would say, OpenVZ is United States of Linux because i can run all my lovely different type of GNU/Linux distributions(States) on one single machine with one kernel model. As stable as guaranteed for production server and handy for software development (well no more dual, tri, quad boot partition). After all, it is just a good quality software piece for Linux User. Again, welcome to United States of Linux world!!
Victor, System Admin, kholix.com
Thanks for producing OpenVZ, we use it ourselves at PlanetMirror and find that it's fantastic.
Robert McLeay, PlanetMirror.com stuff
OpenVZ is about the greatest thing we've ever found, and we're SO glad for it.
Gregor Mosheh, HostGIS 
OpenVZ has me seriously impressed, I was looking to try virtualisation technology and got OpenVZ up and running in only 3 trips to the coffee machine! -barf
We've been running OpenVZ in a production environment for a few years for a multitude of tasks. It's been nothing short of amazing, stable, and resource friendly! Thanks to all those who have contributed to make OpenVZ even better over the years!
Eric Thern, Technical Director, Zoidial Hosting and VPS
Hello all, just downloaded and installed OpenVZ, and i must say its a big improvement over other container systems that i have tested IMHO. 
Virtuozzo and openvz are wonderful - I don't know why more people aren't using them. I hear a lot of hype for xen and usermode but virtuozzo/openvz is so great for many common needs. 
For my needs, OpenVZ is better than Xen. The one-kernel approach conserves memory, leaving more for applications. And having all container in one disk partition saves disk space. A surprise bonus was the template cache management with yum. The ease of keeping templates updated and quickly installing new operating environments is yummy! 
I agree with you very much. I would say for enterprise use where cost/efficiency is not a factor, Xen has an edge over VZ. However for a service provider or other situation where CPU/RAM/DISK resources are shared among environments to ensure profitability/efficiency, openvz is far superior. Also, VZ is much simpler to use, and all of the command line utilities are well documented. 
Last week when we were in limbo about what to do, it was decided to try out XEN Virtualization. From what is written in the press the Xen system has alot of promise, Features such as opensource with live migration and backups sounds great; but was far too complicated to get working in our configuration. OpenVZ was the only virtual server system that was simple to install and get working. 
It still amazes me how well OpenVZ works. 
[03:30:15] <pookey> well, I've been using openvz for all of about an hour, and I'm pretty impressed so far :)
from #openvz IRC channel
I am playing around for years with all major virtualization environments like all VMware products, Microsoft and several xen based solutions. But OpenVZ is the overall winner. 
I messed around with VMWare and Xen. I found VMWare to be somewhat over kill and Xen was damned hard to get working. The user community on the Xen mailing list is rather hostile. It looked like A number of people hang out there for the sole purpose of flaming the clueless.
I've found the OpenVZ folks to be very helpful and knowledgeable. OpenVZ is simple to install and get running. It pretty much satisfies my needs. 
I'm a sysadm and have always used xen/qemu/virtualbox/vmware server for my VMs and my customer's ones. Yesterday I decided to give OpenVZ a try and... I'm amazed. It's fast, easy and reliable.Live migration works like a charm and the use of rsync assures low data transfers. Great.  Stefano Marinelli, http://www.dragas.net
OpenVZ is one of the few pieces of software that I truly love. It works wonderfully. It should become part of the mainline kernel. Nick Andrew, http://www.nick-andrew.net
And thanks again for OpenVZ. Our business couldn't do what we do, as well as we do, with VMWare or Xen. Gregor Mosheh, System Administrator, HostGIS cartographic development & hosting services.
Thank you for OpenVZ by the way... it is awesome. It saves me hours of work every day. Eric Gearhart, http://nixwizard.net
For us at Signet, OpenVZ is ideal as a virtualization platform as it's open-source, no vendor lock-in's and great performance. It perfectly integrates into our high-availability SAN and server setup so it's great. Remco Bressers, http://www.signet.nl
Indira Gandhi National Open University, India (IGNOU) is the world's largest open university in terms of student enrolments (2.5 + million approx.) for different programmes. Catering web based services to such large student fraternity is indeed a hard task. The systems and services were heavily biased towards proprietary corporations products, thereby, aggravating the quality of service to its intended audience. Moreover, virtualization was a blackbox to the IT department of IGNOU, until May 2009. Thereafter the entire networks and systems were stunned to see at least 4 Mediawiki sites , 1 tomcat based Java application, 2 Subversion server for in-house development & networking team, 1 egroupware server on a single SUN Fire X 4140 powered by Debian & OpenVZ. All the services are live with downtime of 5 hours(due to electrical outage, ISP downtime) since May 2009 till date. That makes 99.91 % uptime. Kudos to OpenVZ team for making this possible. --Sukant Kole, ACIIL23:37, 13 January 2010 (UTC)
OpenVZ helps companies and SMEs who wish to get benefit from IT softwares at a low cost in equipment and electricity. Easy to implement and scalable from a simple to a more complex infrastructure, OpenVZ is currently the best solution we found to run safely an elastic range of SaaS services from the GNU free software suite, and therefore, achieve our business objectives and those of our clients. OpenVZ helps us also to make efficient backups of our servers using rsync and SSH tools and replication for high availability enterprise infrastructure, because that's the most important.
Secure jailing and virtualization, promotes green and energy efficient technology, elastic, easy replication and backups : those are the reasons why we trust and choose OpenVZ.
David Côté-Tremblay, SOLIB Québec - Linux, Logiciel Libre et Open Source
OpenVZ keeps my spam filtering business running
I'm in the spam filtering business, Junk Email Filter and I'm running OpenVZ on everything. I love the virtualization for several reasons. In spam filtering there is a lot of redundancy and duplication across machines. I have a network of front end Exim servers as a front end MTA. I also have Spam Assassin virtual servers, regular name servers, caching name servers, RBL servers, post processing spam servers, and servers gathering statistics and building white and black lists.
By modularizing the functions and creating multiple OpenVZ servers I can move virtual machines from computer to computer to balance loads across several physical servers. I can create servers with different permissions so that many of these servers are more secure in that they only have root as the only real login user. If I need to expand I just buy more computers and populate them with the right combination of virtual servers.
I chose OpenVZ over other virtualizations because OpenVZ is fast and efficient. It is in fact the most fast an efficient because it sacrifices some of the features of true virtualization. It's Linux only and has a single kernel. But my needs are Linux only and OpenVZ has almost no overhead at all. It doesn't leave memory fragmented into virtual machines that never use all their ram. Instead the memory limits are just caps and memory usage depends on what you run.It's fast, it's simple, and it just works. —The preceding unsigned comment was added by Mperkel (talk • contribs) 17:23, 22 January 2010.
Now My favorite utility
OK: I did discover that it has serious failings when used as an FTP server. But I can run 3 complete and independant web servers on a Pentium-4 machine with 512 Meg ram and a single 80 Gig drive with space, memory, and cycles to spare!! KILLER!
We now have a true server class machine running about 120 client web sites used for accessing a special web application. I think LXC might do that, I could not deploy and tune so many in a year: with openvz I could do that many in a week. It would only take THAT long because of the individual data links for the application.
I just wish Corporate would allow me to purchase commercial product to gain the central management!
Im no way close to even being an amateur Linux System Admin. But this by far blows all other products ive worked with, with flexebility and ease of configuration
Virtualization solution Found!
Looking for a Virtualization solution to add VPS services to my company, OpenVZ works perfectly! - Chad in NY
The best option for what we do
We have no other reason to choose any other software! OpenVZ is deficiently the correct choice for our VPS Services.
Works very well for what we do. Low overhead and no problems hosting a real time application. The guys who work on the OpenVZ kernel are amazing.
Works really well and is very stable! We haven't faced any issues yet and the community is great. Jay Svoboda, Tailored VPS
Our VPS are based on OpenVZ, the best solution we found so far for our Cloud VPS services, no issues so far and great server performance. From Infranetworking's Twitter Account - Esteban Borges, https://www.infranetworking.com