HP-UX 11i v3 Crash Dump Improvements

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3.1 Requirements
3.1.1 Platform support
In the initial release of HP-UX 11i v3 only HP Integrity servers will support parallel dump.
Enabling parallel dump on HP 9000 servers will not be allowed.
3.1.2 Driver Capabilities
I/O support during dump is provided via dump drivers, and each configured dump driver reports
its parallelism capabilities to the dump infrastructure. These capabilities are:
• Legacy: new parallelism feature is not supported
• Reentrant: supports parallelism per HBA port
• Concurrent: supports parallelism per dump device
The HP-provided dump drivers have the following capabilities in the initial HP-UX 11i v3 release:
Table 1: Driver Parallelism Capabilities
Dump Drivers Parallelism Capability
fcd
Concurrent
td, mpt, c8xx, ciss, sasd
Reentrant
3.1.3 Dump Units
A Dump Unit is an independent sequential unit of execution within the dump process. Each dump
unit is assigned an exclusive subset of the system resources needed to perform the dump,
including CPUs, a portion of the physical memory to be dumped, and a subset of the configured
dump devices. The dump infrastructure in HP-UX 11i v3 automatically partitions system resources
at dump time into dump units.
Each dump unit operates sequentially. Parallelism is achieved by multiple dump units executing in
parallel.
3.1.3.1 Resource Requirements
The following requirements must be met to achieve multiple dump units, and hence parallelism:
• Multiple CPUs:
o One CPU per dump unit for an uncompressed dump. E.g. to achieve 4-way parallelism
(4 dump units) in an uncompressed dump, the system must have at least 4 CPUs.
o Five CPUs per dump unit for a compressed dump (4 CPUs compressing data and one
CPU writing the data to the disks).
• Multiple dump devices:
o A dump device cannot be shared across multiple dump units. Therefore, to
achieve N dump units at least N dump devices must be configured, subject to driver
constraints listed below:
o Devices controlled by legacy dump drivers: multiple “legacy devices” cannot be
accessed in parallel, so all such devices will be assigned to a single dump unit.
o Devices controlled by reentrant dump drivers: multiple “reentrant devices” can
be accessed in parallel only if the devices are configured through separate
HBA ports. Thus all “reentrant devices” on the same HBA port will be assigned
to a single dump unit. To achieve, for example, 4 dump units using reentrant
dump devices requires 4 devices each accessible through a separate HBA port.