= Welcome to HAVEN Project =

High availability (HA) refers to a system and associated service implementation that is continuously operational for a long period of time. With respect to the clients, an ideal system never stops working, which also means the system will always respond to the clients’ requests. Whole-system replication is a conventional way to increase the system availability: once the primary machine fails, the running applications will be taken over by the backup machine. However, there are several limitations that make this method unattractive for deployment: it needs specialized hardware and software, which are usually expensive. The final system also requires complex customized configurations, which makes it hard to manage efficiently. 

As virtualization becomes more and more prevalent, we can overcome these limitations in the virtual world. All the applications are running in the VM, so now it’s possible to implement the whole-system replication in an easy and efficient way — by saving the copy of the whole VM running on the system. As VMs are totally hardware-independent, the cost is much lower compared to the the hardware expenses in traditional HA solutions. Besides, virtualization technology can facilitate the management of multiple VMs on a single physical machine. With virtual machine monitors (VMM), the service applications are separated from physical machines, thus provides increased flexibility and improved performance.

HAVEN means "High Availability in Virtualized Environment with Networking". It consists of several finished and ongoing projects which aim on addressing the availability and reliability challenges in virtualized system. HAVEN focus on providing transparent and comprehensive high availability (HA) to solo and multiple virtual machines (VM) running on [http://xen.org/ The Xen Hypervisor].

''[wiki:teammember HAVEN Team]''

== Sub-Projects Under HAVEN ==

 * [wiki:Architecture Architecture] -- The prototype architecture
 * [wiki:LLM LLM] -- Our previous effort

== Use HAVEN ==
 ''Prerequisite'' 
 * [http://www.centos.org/modules/tinycontent/index.php?id=15 Install the linux kernel] -- Currently we use CentOS, but other OS like Fedora is also fine.
 * [http://xen.org/products/downloads.html Download and install Xen Hypervisor][[BR]]

 ''Start Using HAVEN'' 
 * [wiki:Source Check out source code]
 * [wiki:Patch Download Patch]

== [wiki:Publications Documentation & Publications] ==

== Related Efforts ==
 Some related and parallel projects with HAVEN are as following: 
 * [http://xen.org/ The Xen Hypervisor] -- Xen Open Source Industry Standard For Virtualization
 * [http://nss.cs.ubc.ca/remus/ The Remus project] -- Remus: Transparent High Availability For Xen
 * [http://www.osrg.net/kemari/ The Kemari project] --  A VM Synchronization Mechanism For KVM
 * [http://friends.cs.purdue.edu/dokuwiki/doku.php?id=vnsnap The VNsnap project] --  Take A Snapshot For Entire Virtual Networked Environment