Data Maintained by the Management Processor

HP nPartition severs contain one active management processor (MP). The MP is responsible for a variety of tasks; the most notable are the following:

• maintaining the configuration of the entire complex

• allowing access to the console and console logs for each nPartition

• storing the chassis and event logs

• providing a command menu for performing actions on the complex

• presenting the virtual front panel (VFP) interface

The remainder of this section focuses on how the management processor maintains the configuration of the nPartitions, cells, and other configuration aspects of HP nPartition servers. The configuration data for HP nPartition servers is stored on the MP. The MP provides an interface for management applications such that administrators may configure the complex. Understanding the basics of how the data is stored on the MP provides great insights into HP nPartition server administration, configuration, and troubleshooting. Three primary data structures are stored on the MP: stable complex configuration data (SCCD), dynamic configuration data (DCD), and partition configuration data (PCD).

The SCCD structure contains several crucial pieces of data involved in the management of nPartitions. Most important, the SCCD contains the mapping of cells to nPartitions in the cell assignments array. Changes to a complex's configuration such as adding or removing cells from an nPartition are achieved by modifying the SCCD data structure. Table 4-2 lists the most notable fields in the SCCD data structure and their relevance to nPartition management.

Table 4-2. Key Fields in SCCD Data Structure

Field in SCCD	Importance
Cell Assignments Array	This field is an array with an element for each cell. The value contained in each array index indicates the partition ID to which the cell is assigned.
Complex Name	This field is the descriptive name of the complex.
Serial Number	The serial number is a read-only value representing the serial number of the entire complex.
Cell Type	This field determines whether the cell is to be used as a base cell (default) or floating cell. Currently only base cell types are supported.
Interleaved Memory	This field contains the memory configuration for each cell.
Specifications	A cell's memory can be configured as interleaved, cell local (which means no interleaving) or it may be a mix of the two.

The dynamic configuration data structure is used by the Instant Capacity, Temporary Instant Capacity, and Pay per use solutions. See the respective chapters for details on each of those VSE components.

The partition configuration data contains data for each nPartition. Each nPartition in a complex has a unique PCD data structure. Therefore, as many as sixteen separate PCD data structures could be present in a fully configured HP Superdome server containing sixteen nPartitions. Table 4-3 lists the most notable fields in each PCD data structure and their relevance to nPartition management.

Table 4-3. Key Fields in PCD Data Structure

Field in PCD	Importance
nPartition Name	This field contains a descriptive label for the nPartition. It is not necessarily the same as the hostname for the nPartition and is typically used to describe the workloads running in the nPartition.
Core Cell Choices	This field contains the user-specified order in which the core cell should be chosen. Should the first cell specified in this list become unusable as a core cell, firmware will proceed to the next cell in the list. If the list of core cell choices is not specified by the user, firmware will use the default algorithm to choose the core cell for the nPartition, generally based on the cell with the lowest cell ID that is capable of being a core cell.
Use on Next Boot	This field indicates whether each of the cells should be integrated into the nPartition the next time a reboot or shutdown for reconfiguration is performed on the nPartition. This field is typically used for Instant Capacity licensing purposes or for situations where a cell has experienced a hardware failure and should not be integrated into the nPartition until it can be repaired.
Admin IP Address	This field contains an IP address which can be used for administrative purposes to communicate with the operating system running in an nPartition. This field requires manual setting by administrators with the nPartition command line interfaces. If this value is set, management tools such as Partition Manager are able to communicate with each nPartition in the complex to gather operating systemspecific information such as the operating system type and version.
Boot Paths	This field allows up to three boot paths to be specified. The primary, high-availability alternate, and alternate boot paths are all stored in this field. The PCD is only used for storing boot paths on HP 9000 nPartition servers. HP Integrity nPartition servers use a different storage location. As a result of this difference, when managing HP 9000 nPartition servers, boot paths are visible for all nPartitions in the complex. However, management tools on HP Integrity nPartition Servers are capable of reading the boot paths for only the nPartition where the management tools are running.