Physical Machines and Virtual Machines

Stratus Redundant Linux software running on one physical machine (PM), which is also referred to as a node, creates a single-node ztC Edge system that can create a virtual machine (VM) from scratch. The system can also import existing VMs from other environments and convert them into guest VMs. You can add a node to a single-node system to create a dual-node ztC Edge system. On a dual-node system, the management software automatically provides high-availability (HA) or FT-class protection of the VM (based on the VM configuration) by creating an identical instance of the selected VM on a second host PM. The system administrator manages this single VM entity from a separate, browser-based management console called the ztC Edge Console.

Neither the application nor the user is exposed to the redundant computing resources on the two host PMs. The application sees only one hostname, one MAC address for each network interface presented to the VM, and one IP address for each VM network interface presented to the VM. A system administrator loads and configures the applications on the guest VM—just as if the system administrator were loading them onto a physical server. If a fault or failure occurs in a disk or network device, the software automatically redirects I/O to the paired host PM for continuous operation. Though redundancy is lost until the failure is repaired, the VM continues to operate normally. The application continues to execute as if nothing had happened. The redundancy, fault detection, isolation, and management are completely transparent to the Windows or Linux environment and the application running within it. Repair of the PM is equally transparent and automatic. When a failed component on the PM is repaired, the software automatically incorporates the repaired components into the protected environment of the guest VM and restores redundancy transparently.