= Welcome to Resilire Project =

High availability refers to a system and associated service implementation that is continuously operational for a long period of time. Whole-system replication is a conventional way to increase system availability -- once a primary machine fails, the running applications are migrated and resumed on backup machine(s). However, there are several limitations that make this method unattractive for deployment: it needs specialized hardware and software, which are usually expensive. Additionally, such a system may also require complex customized configurations, which are difficult to manage and maintain.

These limitations are efficiently overcome by virtualization: all applications now run on a virtual machine (VM). Thus, whole-system replication can easily and efficiently be implemented -- a copy of the whole VM is continuously checkpointed and saved on a backup machine. As VMs are totally hardware-independent, the cost is much lower compared to the hardware expenses in traditional high availability 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, providing increased flexibility and improved performance.

The Resilire project is developing techniques and mechanisms for high availability through VM migration, from solo VMs to multiple VMs running on different physical hosts, interconnected by a virtual network (i.e., virtual distributed environments or VDEs). The effort is based on Xen 3.4 VMM, but is portable to more recent releases of Xen and other VMMs with full virtualization. The project's implementations do not require modifications to applications or guest OSes inside the VMs. 

''[wiki:teammember Resilire Team]''

== Resilire in progress ==

 * [wiki:VDEchp VDEchp] -- Globally Consistent Checkpointing for Virtual Distributed Environments
 * [wiki:FGBI FGBI] -- Fine-Grained Block Identification
 * [wiki:LLM LLM] -- Lightweight Live Migration

== Using RESILIRE ==
 ''Prerequisites'' 
 * [http://www.centos.org/modules/tinycontent/index.php?id=15 Install the linux kernel] (CentOS, but other OSes are also fine)
 * [http://xen.org/products/downloads.html Download and install Xen Hypervisor]
 * [http://nss.cs.ubc.ca/remus/index.html#download Install Remus for sub-projects LLM and FGBI] (skip this for only trying VDEchp) [[BR]]

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

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

== Related Efforts ==
 
 * [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] --  Snapshots for Virtual Networked Environments