Q. What is a Virtual Private Server?
A. Virtual Private Servers are the most advanced step in server virtualization technology. They are used to partition a single physical server into many (as many as 1000) isolated virtual private servers. Each virtual private server looks and behaves exactly like a real networked server system, complete with its own set of init scripts, users, processes, filesystems, etc.
Q. What Applications could be run within the Virtual Private Server?
A. Most of applications can be installed within of the Virtual Private Servers without any modifications. Our customers are using Oracle, DB/2, Weblogic, Websphere and other commerical applications quite succesfully. Applications and services do not have to be aware of Parallels Virtuozzo Containers. However, direct access to hardware is not available.
Q. Who needs Parallels Virtuozzo Containers?
A. The short answer is - every system administrator needs it. Some examples of practical applications:
- Hosting - all ranges on the same platform, from low-level shared to medium-power virtual server to powerful dedicated servers - seamless scaling up in the same safe virtual private server.
- Server consolidation - put together your existing servers and use more powerful and reliable hardware.
- Increase availability - keep an up-to-date copy of your virtual private server on another server, and start it in seconds in case of failure
- Education - each student gets its own virtual server with root access
- Testing - safe experimentation on the machine that runs another services
- Clean sandbox - install each service in its own freshly created Virtual Private Server, and you will never have to resolve dependency problems.
- Multiversioning - keep "snapshots" of the project you are working on and be able to switch back and forth in seconds
- Improve network services security - run each server in its own Virtual Private Servers. If the application has a security hole, only this particular virtual private server will be compromised, never the whole system.
Q. What are highlights of Parallels Virtuozzo Containers technology?
A. In short, Parallels Virtuozzo Containers is the only highly scalable virtualization technology with near-zero overhead, strong isolation and rapid customer provisioning that's ready for production use right now. Deployment of Parallels Virtuozzo Containers improves efficiency, flexibility and quality of service in the enterprise environment.
Q. How scalable is Parallels Virtuozzo Containers?
A. Parallels Virtuozzo Containers technology scales up pretty well - we've tested it on machines up to 8CPU and up to 64GB of RAM. If that's not enough, hundreds of servers could be efficiently managed from a single GUI console. Besides, single virtual private server could be scaled up from taking a little fraction of available resources up to all resources available dynamically - you do not even have to restart the virtual private server.
Q. How Parallels Virtuozzo Containers improves efficiency of services?
A. Parallels Virtuozzo Containers is able to lower Total Cost of Ownership and improve Return On Investment in many ways. For existing hardware, it allows to utilize its processing power better by improving average load from 3-5% to at least 30-50%, while still providing ability to handle peak loads. To decrease complexity, Parallels Virtuozzo Containers provides standardized and centralised server management, logically decoupled from actual hardware. And when its time to buy new servers, you can now use few more powerful servers instead of many little ones - with added benefits of better reliability, better peak performance and typically longer lifespan.
Q. How Parallels Virtuozzo Containers improves flexibility of services?
A. By providing unified scalable platform with such unique features as rapid application and updates provisioning. Each Virtual Private Server is hardware independent and can be moved to another Parallels Virtuozzo Containers-based system in seconds over the network. This allows for ease of hardware maintenance (move out all VPS and do whatever you need with the box) and improved availability (keep a syncronized copy of your virtual private server elswere and start it up when primary service failed). If your old box is not able to cope with peak load anymore, just move your VPS to a new one - as simple as drag-n-drop in GUI.
Q. What is a performance overhead?
A. Near zero. There is no emulation layer, only security isolation, and all checking is done on the kernel level without context switching. In fact, some tests show slight improvement of performance under Parallels Virtuozzo Containers.
Q. What are performance expectation?
A. Peak performance is achieved when only one VPS has active tasks. In this case, it could use 100% of available resources - all CPUs, all physical memory, all disk and network bandwidth. Virtuozzo is not limiting you to a single-CPU virtual machine.
Q. Is it possible to move a Virtual Private Server from one server to another?
A. Yes. More over, special patent-pending algorithm is employed to minimize downtime and ensure no data is lost in the process. All you need is a fast network connection between the servers.
Q. What is a VE Network Device (venet)? How does the virtual network work?
A. This is a virtual device that provides a high-speed network connection to the host OS. Zero-copy design principles ensure highest possible performance. This virtual device supports all advanced control capabilities available in Linux. More than one device could be created. In the Virtual Private Server, you can have your own firewall rules and local routing table. You can run packet sniffer to diagnose network problems with your own Virtual Private Server. However, there is absolutely no access to any packets sent to another Virtual Private Servers.