Physical Machines and Virtual Machines

A ztC Edge system, which runs Stratus Redundant Linux software on two physical machines (PMs), also referred to as nodes, transparently protects applications by creating redundant virtual machines (VMs) that run on both nodes.

Stratus Redundant Linux software also runs on a system with one PM, when licensed for one node. For information on systems licensed for one node, see ztC Edge System Description. The information in the rest of this topic applies to systems licensed for two nodes.

The Stratus Redundant Linux management software can create a guest VM from scratch. It can also import existing VMs from other environments and convert them into guest VMs. By creating an identical instance of the selected VM on a second host PM, the management software automatically provides high-availability (HA) or FT-class (based on the VM configuration) protection of the VM. The system administrator manages this single entity from a separate, browser-based management console called the ztC 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.

Related Topics

Using the ztC Console

The Physical Machines Page

The Virtual Machines Page