Open Source IT: Linux on Big Iron: 41,400 copies of Linux running on one box? No problem.Mar 29, 2000, 03:22 (2 Talkback[s])
(Other stories by Daisy Whitney)
[ Thanks to Dan Orzech for this link. ]
"There are three ways to run Linux on an S/390: native, in a logical partitioning environment (LPAR) or under VM/ESA. Running Linux natively means it is the only operating system and the it controls the whole machine. When run in LPAR, the system resides on its own separate piece of the physical hardware, so that the machine can actually run several different operating systems on the same hardware."
"VM/ESA -- virtual machine/enterprise systems architecture -- is IBM's operating system that allows you to simulate a complete computer environment in software. Multiple copies of Linux can run side-by-side on a mainframe under VM/ESA, each one operating as if it was on its own box. So far, most Linux mainframe users seem to favor running it under VM/ESA."
"Just how many virtual copies of Linux can you run on an S/390? David Boyes, a Virginia-based engineer, has gained some notoriety in the Linux community for his "Test Plan Charlie" effort in which he ran 41,400 copies of Linux on the same S/390 CPU. "Each virtual machine was a complete multi-user network-accessible Linux system configured for a specific task," he said. "Some generated web traffic, some handled network connectivity, others were applications servers, others were shared file servers." The system ran smoothly, although it did slow as more virtual systems were added. It did not crash, however, Boyes says, even when VM ran out of resources to allocate."