Remus Project Brings Transparent High Availability To Xen
An anonymous reader writes "The Remus project has just been incorporated into the Xen hypervisor. Developed at the University of British Columbia, Remus provides a thin layer that continuously replicates a running virtual machine onto a second physical host. Remus requires no modifications to the OS or applications within the protected VM: on failure, Remus activates the replica on the second host, and the VM simply picks up where the original system died. Open TCP connections remain intact, and applications continue to run unaware of the failure. It's pretty fun to yank the plug out on your web server and see everything continue to tick along. This sort of HA has traditionally required either really expensive hardware, or very complex and invasive modifications to applications and OSes."
They may have a patent too!!
VM replication like this still has an IO bottleneck. This isn't magic: unless you move to infiniband you're not going to touch something like a Stratus or NonStop machine. By the time you add in the cost of the high-perf interconnects, you're on-par with the real-time boxes. All this convergence going on with people redesigning the mainframe but ass-backward with client/server gear. Makes little sense to me other than it being a gimmick.
By the time you get all the components that provide the processing and I/O throughput of those high-end boxes, the x86/64 commodity hardware cost advantage has evaporated.
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