OpenVMS Galaxy software controls operating system instancesthrough shared memory; it implements a resource-sharing associationbetween instances in multiple soft partitions. Multiple independentoperating system instances can run in multiple soft partitions withoutGalaxy. For additional information about OpenVMS Galaxy concepts,see OpenVMS Galaxy Concepts. Tocreate multiple soft partitions, use the Galaxy procedures as describedin Chapters 4 through 10, depending on your hardware.
The configuration tree enables the manipulation of resourcesup and down the tree within each hard partition. The tree definesa hierarchy of physical connectivity and resource ownership. Hardwareresources can be assigned ownership at one of several levels, althoughresources are allocated and used by an instance. An instance isan operating system running within a soft partition.Software partitionsgovern system resources. CPUs are used only when owned by a softpartition and manipulated by the instance running there; however,CPUs may be owned by higher levels of the configuration tree –– makingthem visible and available to all instances equally. If boot ownershipis not set before a platform box is powered up, and a CPU moduleis later added to the system, that CPU is owned by the hardwarepartition to which it was added, and it is programmatically assignableto any of the soft partitions within that hard partition. (The ES47/ES80/GS1280does not support hot swap of components.)
As soon as an instance of the operating system boots, allits resources are exclusively owned by the soft partition to whichit is assigned: only that instance can manipulate its state characteristics.Consequently, it is important to consider the initial allocationof CPUs at powerup –– even those that do notcurrently exist –– to provide the best divisionof resources when they become available.
To create multiple soft partitions within a single hard partition,use standard partitioning procedures, as previously described, tocreate Galaxy configurations with instances running in these softpartitions. How Memory Is Used illustrateshow memory is used in a Galaxy instance. Soft partitions requirethe OpenVMS minimum for memory.
Figure 8 How Memory Is Used
The Galaxy ID is within the hard partition and can span thehard partition. That is, if you have two hard partitions and yourun Galaxy in both, each Galaxy will have its own unique GalaxyID. Keep this in mind when you use network management tools; theywill also see two Galaxy environments when two Galaxy IDs exist.
Soft Partitioning in the Configuration Tree illustrates fourhard partitions (0, 1, 2, 3), each of which has a uniquename such as hp0. Within hard partition 0,a Galaxy is shown that contains two softpartitions, the left-most sp1 and sp0.Other Galaxies exist in each of the other hard partitions, as couldmultiple independent operating system instances if none of themcreates or joins a Galaxy. You can run an operating system instancein any soft partition.There is one Galaxy per communitybecause the shared memory used by the Galaxy is owned by the community. This makes it visible and accessible to all instances in the Galaxymembership. All instances running in soft partitions below the communitynode are potentially eligible to join the Galaxy there. Member nodesmay take advantage of the shared resources controlled by the Galaxy.Although independent instances are still able to assign and migrateCPUs, only members of the Galaxy can take advantage of the benefitsof shared memory.There can be only one community per hard partition.
Figure 9 Soft Partitioning in the Configuration Tree
HP OpenVMS Alpha Partitioning and Galaxy Guide
Managing Workloads With Partitions
