The following list of terms is( used throughout the remainder of this chapter and in the vPar product documentation.
Virtual Partition Database is where the configuration of every vPar in the server is represented. The default location for the vPar database is /stand/vpdb. If this file does not exist when the command to create the first vPar is executed, the file will be created. When the vPar monitor is loaded, it reads the vPar database into memory. Upon booting each of the vPars, a copy of the vPar monitor's in-memory database is written to the file system for every vPar in the server. This results in all of the vPars having a current copy of the vPar configuration. The vPar infrastructure also supports alternate databases, which allows for differing configurations based on the database loaded by the monitor.
Virtual Partition Monitor is the layer shown in Figure 5-2 that intercepts the operating system's firmware calls and filters the responses appropriately.
Bound CPU is a CPU that services I/O interrupts. Starting with HP-UX 11i v2, interrupts can be dynamically migrated. However, previous releases of HP-UX did not support interrupt migration, therefore a bound CPU can be added or removed from a vPar only while the vPar is down. Since bound CPUs service interrupts, it is recommended vPars with I/O-intensive workloads have more bound CPUs than unbound CPUs. There are two subtypes of bound CPUs, monitor bound and user bound.
Monitor-Bound CPU is a CPU bound by the monitor as a result of meeting the minimum number of CPUs assigned to a vPar. Monitor-bound CPUs are chosen by the monitor at boot time and cannot be dynamically migrated from one Virtual Partition to another.
User-Bound CPU is a CPU bound because the user has explicitly specified the path of the CPU to be assigned to a vPar.
Unbound CPU is a CPU that does not service interrupts. Unbound CPUs can be dynamically migrated from one vPar to another while the vPars are in the up state.
Unbound CPUs are ideal for CPU-intensive workloads, especially in environments where migrating CPUs enable higher server utilization.
Minimum CPUs is the minimum number of CPUs to be assigned to the vPar. This value represents the number of CPUs that will be bound by the monitor if no CPUs are explicitly assigned.
Maximum CPUs is the maximum number of CPUs that can be assigned to the vPar. The sum of bound and unbound CPUs cannot exceed this value.
Memory Size is the amount of memory in MB assigned to the vPar. The memory size must be in multiples of 64MB. Memory sizes that are not multiples of 64 MB will be rounded up to the nearest 64MB boundary.
Memory Range is a specific base address and size that dictates exactly which range of memory should be assigned to the vPar. Memory ranges should only be used with systems and applications that support non-uniform memory access (NUMA) architectures.
Local Bus Adapter (LBA) is the hardware layer that can be assigned to a single vPar. The assignment of an LBA to a vPar assigns the I/O slot, the contained PCI card, and all devices attached to the PCI card.
Explicit I/O Path is the path of the LBA being explicitly assigned to a vPar. All devices below the specified LBA are owned by a single vPar.
Implicit I/O Path is the path of an LBA that is implicitly assigned to a vPar as a result of a device below the LBA being assigned to a vPar. This situation typically occurs when a boot device is assigned to a vPar but the LBA containing the boot device is not explicitly assigned to the vPar.
Boot Attributes are added to an I/O path to specify the primary and alternate boot paths for a vPar's operating system. Configuration of boot paths is a mechanism commonly used to assign implicit I/O paths. This situation is illustrated in the example scenario below.