Double-Take Availability combines continuous real-time replication and automatic failover capabilities for disaster recovery, high availability, and centralized backup on physical or virtual Windows servers. Double-Take Availability uses patented replication and failover capabilities that continuously capture byte-level changes as they occur and replicates those changes to another server either locally or over any WAN link.

Double Take Availability captures disk-writes at the host’s file system layer while all applications (including virtual machines writing to virtual disks) operate above the actual file system layer. This allows the solution to transparently and reliably protect that data by replicating it via its normal mechanisms to a target server running another copy of Double-Take Availability. On the target side, Double Take Availability simply applies the same file update commands to the duplicate files that reside on the target server – sending only real-time byte-level changes across any IP connection.

Windows Requirements:

• Windows Server 2003 / 2008 Standard, Enterprise and Datacenter Editions (32-bit / 64-bit)
• Microsoft Windows XP

Hyper-V Requirements:

• Microsoft .NET 3.5 SP1
• VMs stored on a standard NTFS file system
• TCP/IP with static IP addressing or reserved DHC addressing for Hyper-V hosts
• Windows Server 2008 Standard, Enterprise and Datacenter (64-bit)

VMWare Requirements:

• VMware VirtualCenter 2.x or later
• VMware ESX Server 3.x or later
• 130 MB disk space for programs