VPS Hosting India, Virtual Private Server Hosting, Virtuozzo, OpenVZ, Hyper-V, Xen Linux and Windows VPS
Virtual Private Server Hosting (VPS Hosting): A Virtual Private Server also called as Virtual Dedicated Server provides a feature of multiple virtual servers on a single physical server. Virtual server application divides the physical server into multiple virtual servers. Each virtual server has its own dedicated resources and operating system. Virtual server application divides the single physical server into many servers virtually, so it is called Virtual Private Server. Each virtual server can run its own operating system and can be controlled independently. Each virtual dedicated server has its own disk space, bandwidth, CPU allocation and memory. Virtual web hosting physical server hardware is controlled by the web host. Virtual servers, their operating system and applications are controlled by each vps owner. VMware, Xen, FreeBSD Jail, User-mode Linux, Linux-VServer, FreeVPS, OpenVZ, and Virtuozzo are Virtualization technologies. Among these technologies Virtuozzo, VMware, Microsoft Virtual Server and Xen are widely used by web hosting companies.
In simple words Virtual Private Servers are like housing apartments. Each apartment has same feature but it is occupied by different persons, like that Virtual Private Server is divided into different servers with same resources but used by different web sites. In virtual private server hosting each virtual server is allocated with defined dedicated resources which can only be used by that VPS. Main physical node has total RAM of more than 4GB. Suppose this node is divided into 16 virtual servers. Each virtual server can get approximately 256MB of RAM and equal share of CPU resources. Amount of resources can be allocated differently for each virtual server. Number of maximum virtual servers a physical node can contain depends on the total available resources in it. Each VPS runs independently, each one has its own file system so that other VPS cannot interfere into their system. So VPS gets almost all features like a physical Dedicated Server.
In virtual private hosting environment, first, the physical server node boots with operating systems (OS) like Windows Server or Linux Server. After the physical server node boots up, it runs virtualization application which boots each virtual server within virtualization environment. Virtual servers does not get direct access to the hardware of the server and these servers are booted through the disk image. There are 2 kinds of virtualization environments: software based and hardware based. In a software based virtualization environment, the virtual machines share the same kernel (kernel is central module of any operating system. It is a module of operating system that loads first, and it remains in main memory) and actually require the main node's resources. This type of virtualization normally has many benefits in a web hosting environment because of quota incrementing and decrementing in real time with no need to restart the node. Example for software based virtualization environment are Virtuozzo and HyperVM. Microsoft Virtual Server, VMware ESX Server and Xen provides hardware based virtualization environment. In hardware virtualization environment, real hardware resources and no burst and/or realtime quota modification is possible.
Virtual Private Server Technologies
Virtuozzo : Virtuozzo is a proprietary operating system-level virtualization product produced by Parallels, Inc. Both windows and Linux. Parallels Virtuozzo Containers creates multiple, isolated containers (otherwise known as virtual environments (VEs), or Virtual Private Servers (VPSs)) on a single physical server. Parallels Virtuozzo Containers virtualizes at the operating system level, rather than the hardware level as other Virtual Machine (VM) products frequently do. This allows the sharing of hardware, systems management effort, and sometimes software licenses among different workloads. A container behaves in most respects as if it were a stand-alone server.
Parallels Virtuozzo Containers was designed to be a low-overhead, fast-performing solution with many tools for simple management, since its early adopters include service providers with thousands of containers to manage. The technology is based on a single OS flavor for a server, which means that a Windows server can only host Windows containers and that a Linux servers can only host Linux containers.
OpenVZ: OpenVZ is container-based virtualization for Linux. OpenVZ creates multiple secure, isolated containers (otherwise known as VEs or VPSs) on a single physical server enabling better server utilization and ensuring that applications do not conflict. Each container performs and executes exactly like a stand-alone server; a container can be rebooted independently and have root access, users, IP addresses, memory, processes, files, applications, system libraries and configuration files.
Microsoft Hyper-V : Microsoft Hyper-V which is a hypervisor-based technology that provides true Hardware Virtualization and High level of Isolation from other virtual machines on the physical server. With the use of this new virtualization technology, users no longer have to worry about having their services affected by other resource intensive services running on the same box. Microsoft Hyper-V Server 2008 is a stand-alone product that provides a reliable and optimized virtualization solution enabling organizations to improve server utilization and reduce costs.
Xen : Xen is a free software virtual machine for IA-32, x86-64, IA-64 and PowerPC 970 architectures. On most CPUs, Xen uses a form of virtualization known as paravirtualization, meaning that the guest operating system must be modified to use a special hypercall ABI instead of certain architectural features. Intel has contributed modifications to Xen to support their VT-x (formerly Vanderpool) architecture extensions. Similarly AMD has contributed support for their AMD-V extensions. These technologies, while differing quite substantially in their implementation and instruction sets, are managed by a common abstraction layer in Xen and enable unmodified guest operating systems to run within Xen virtual machines, starting with Xen 3.0. Operating systems supported as guest includes, almost all distributions of Linux, Microsoft Windows, Free BSD, Open BSD, Open Solaris and Netware.
VMware : VMware provides two classes of application, Workstation and Server. Workstation allows users to run multiple instances of x86 or x86-64 -compatible operating systems on a single physical PC. VMware Fusion provides similar functionality for users of the MacIntel platform, along with full compatibility with virtual machines created by other VMware products. For users without a license to use VMware Workstation or VMware Fusion, VMware offers the freeware VMware Player product, which can run (but not create) virtual machines. VMware provides hardware based virtualization environment.
Among server class there are two types, VMware ESX Server and VMware Server. ESX Server, an enterprise-level product, can deliver greater performance than the freeware VMware Server, due to lower system overhead. In addition, ESX Server integrates into VMware Virtual Infrastructure, which offers extra services to enhance the reliability and manageability of a server deployment. The VMware Server product offers a user interface with a similar look-and-feel to VMware Workstation.
Features and Benefits of Virtual Servers
Key benefits of virtual machine technology are isolation, standardization, consolidation, ease of testing, and mobility. One of the key reasons to employ virtualization is to isolate applications from each other. The hardware that is presented to the guest operating system is uniform. Consolidation of servers results in easier management and decreased hardware costs. Virtual machines let you test scenarios easily. Most virtual machine software today provides snapshot and rollback capabilities. Virtual machines are easy to move between physical machines. Most of the virtual machine software on the market today stores a whole disk in the guest environment as a single file in the host environment. Hosting customers gets advantage of reliable enterprise class dedicated server resources at very affordable prices.