The Xtravirt Virtual SAN (XVS) appliance for VMware ESX3 Server, is a free solution to provide the benefits of shared VMFS storage without the cost of a SAN – this allows the utilisation of otherwise unused local storage in the ESX server to facilitate enterprise level features such as vMotion, DRS and HA normally only available through the use of a shared storage device. All volume data is synchronously replicated between hosts, providing full fail-over capability with data integrity in the event of host, disk or appliance failure. The appliance is menu driven and has been designed to be as easy to configure as possible, and full documentation is provided. 

Its features include:

• XVS is a SAN and local Disaster Recovery all-in-one
• It provides enterprise level functionality such as vMotion, DRS, and HA, all using direct attached storage
• All volume data is synchronously replicated between hosts providing full failover capability with data integrity in the event of a host, disk or appliance failure

Download it here