HP-UX 11i v3 Crash Dump Improvements
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3.4.5 Recommended procedure to configure parallel dump for performance
The following outlines a recommended procedure to configure parallel dump for performance:
1. Identify the available devices and HBA ports for dump.
2. Calculate the maximum CPU parallelism for both compressed and uncompressed dump.
3. Calculate the maximum Device parallelism.
4. Calculate the overall dump parallelism based on steps 2 and 3 for compressed and
uncompressed dump. See the formulas at the end of section 3.1.
5. Choose the dump format (compressed or uncompressed) that maximizes the parallelism.
Keep in mind the discussions in sections 3.4.1through 3.4.3.
6. Set up the configuration, if satisfied, or
Go back to step 1 and look at changing the dump configuration or available resources.
3.5 Viewing, Enabling, Disabling of Parallel Dump
3.5.1 Viewing current setting
The current setting of the parallel dump feature can be viewed by running "crashconf -v" (see
crashconf(1m)). The output contains the text "Dump Parallel: ON" if the feature is enabled. If the
feature is disabled "Dump Parallel: OFF" is displayed in the "crashconf -v" command output. See
section 5.2 for example crashconf –v output.
Parallel dump is “on” by default on HP Integrity servers, and is “off” by default on HP 9000
servers. Parallel dump cannot be enabled on HP 9000 servers.
3.5.2 Enabling and Disabling Parallel Dump
Parallel dump can be enabled or disabled at run time by running the crashconf(1m) command
with the new "-p" option. When combined with the –t option, the –p setting can be made
persistent across reboots.
Alternatively, parallel dump can be enabled or disabled on each boot by setting
CRASHCONF_CONCURRENT_DUMP to 1 in the /etc/rc.config.d/crashconf init script. Setting
CRASHCONF_CONCURRENT_DUMP to 0 disables the feature. These settings take effect when
the script is executed during boot.
3.5.3 Determining the driver capability of a dump device
The dump driver corresponding to a configured dump device can be determined by doing the
following:
(1) crashconf –l to obtain the lun path hw path for each configured dump device
(2) Extract the HBA port’s hw path (the portion left of the 1st '.' in the lun path hw path)
(3) ioscan -kf | grep '<hba_hwpath> ' (with a space following the hba port hw path)
The driver name will be displayed in the 4th column. See Table 1: Driver Parallelism Capabilities
for the capability of each of the HP-provided dump drivers.