vPars Monitor and Database

vPars Monitor

For each hard partition, the vPars Monitor manages the assignment of hardware resources to virtual partitions, boots virtual partitions and their kernels, and emulates certain firmware calls. By emulating these specific calls, vPars creates the illusion to each HP-UX instance that it is running on a standalone server, consisting of the hardware that has been assigned to it.

Once a virtual partition is launched, the vPars Monitor transfers ownership of the hardware to the virtual partition. At that point the vPars Monitor is not involved in accessing I/O hardware, physical memory, or process to processor cycles: the individual HP-UX instances have complete ownership of their respective hardware resources. This allows each partition to run at full speed.

The commands for the vPars Monitor are shown in the section “vPars Monitor: Using vPars Monitor Commands”; however, most of the vPars operations are performed using vPars commands at the Unix shell level. For more information on the commands, see the chapter “vPars Monitor and Shell Commands”.

For information on the vPars Monitor memory usage, see Appendix D.

vPars Partition Database

At the heart of the vPars Monitor is the partition database. The partition database contains partition configuration information. Using the partition database, the vPars Monitor tracks which virtual partitions exist and what hardware resources and partition attributes are associated with each partition.

When the vPars Monitor boots (see “Boot Sequence”), it reads a copy of the partition database from a file on the same disk from which the vPars Monitor /stand/vpmon is booted. The default file is /stand/vpdb. Then, the vPars Monitor creates a master copy of the vPars partition database in the memory reserved by the vPars Monitor.

The operating system of each virtual partition also keeps a local copy of the partition database in a file, by default /stand/vpdb, on its local boot disk.

As a preventive action, you can back up the vPars partition database to avoid accidental loss of configuration changes. For more details, see “Network and Tape Recovery” and “Using an Alternate Partition Database File ”.

You can create, modify, and view the database contents using vPars commands at the Unix shell level. See “vPars Monitor and Shell Commands”. Because the format of the database is proprietary, you must use only vPars commands to create, modify, and view the database.

Whenever you execute a vPars command from the Unix shell of a partition, the change is made first to the vPars Monitor’s master copy. Then, the operating system from which you executed the command updates its local copy from the master copy. Every five seconds, the operating system of each running partition automatically updates its local copy from the master copy. This synchronization ensures that the virtual partitions and changes to the partition database are preserved when the entire hard partition is rebooted.

	NOTE: The vPars Monitor can only synchronize to the database files of running virtual partitions. If you reboot the hard partition, you should boot the vPars Monitor from the boot disk of a virtual partition that was running during your most recent partition configuration change.