crashconf(1M)

NAME

crashconf — configure system crash dumps

SYNOPSIS

/sbin/crashconf [-adlorstv] [-i|-e class]... [-c cmode] [-p pmode]... [device]...

DESCRIPTION

crashconf displays and/or changes the current system crash dump configuration. The crash dump configuration consists of:

The crash dump device list. This list identifies all devices that can be used to store a crash dump.
The included class list. This list identifies all system memory classes that must be included in any crash dump.
The excluded class list. This list identifies all system memory classes that should not be included in a crash dump.
The compression mode selection. This selection is used to turn compression ON or OFF, before dumping.
The concurrency mode selection. This selection is used to turn concurrency ON or OFF, before dumping. Currently supported only on Integrity systems.

Most system memory classes are in neither the included class list nor the excluded class list. Instead, the system determines whether or not to dump those classes of memory based on the type of crash that occurs.

Note the system operator may request a full crash dump at the time the dump is taken. In this case, a full dump will be performed regardless of the contents of the excluded class list.

Turning compression mode ON will result in faster and smaller dumps. If the dump is compressed, savecrash will also copy over the dump faster since the dump will be smaller in size.

Since compressed dump requires additional processors and memory to do the compression, the system may fall back on uncompressed dump if it could not identify the processing resources required to do compressed dump.

Turning concurrency mode ON may result in faster dumps depending on the configuration of the dump devices. Depending on the availability of additional memory and the configuration of dump devices, the system may fall back to non-concurrent dump mode.

Any changes to the configuration take effect immediately and remain in effect until the next system reboot, or until changed with a subsequent invocation of crashconf. Using the -t option, changes to the include and exclude class lists and compression mode and concurrency mode can be made persistent across system reboots, but the changes do not persist across kernel rebuilds. Use HP SMH (replacement for SAM) or kctune (see sam(1M), smh(1M), and kctune(1M)) to make tunables persistent. Changes to the dump device list can be made persistent across system reboots by using the -s option.

device specifies a block or character device file name (legacy or persistent) of a device that is a valid destination for crash dumps. The devices listed will be added to, deleted from (using -d) or replaced (using -r) in the current list of crash dump devices.

Note: A device has several device file names associated with it. These include the legacy device file names that correspond to the various legacy paths to the device, and one persistent device file name that corresponds to the lun itself (see intro(7)).

The crash dump subsystem converts the legacy device file name to the persistent device file name prior to starting the configuration. The crash dump subsystem will also use the block device file name for the configuration. Use the -v option to display the persistent device file name. Display the corresponding legacy device file using ioscan (see ioscan(1M)).

The crash dump subsystem can chooose any available path to the device for the configuration. Therefore, the configuration of the device may not always be through the path represented by the legacy device file name. Use the -l option to display the lunpath hardware path (see intro(7)) selected for the configuration.

class is the name (or number) of a system memory class which should be added to the appropriate class list. The list of system memory classes can be obtained using crashconf -v. The memory page size is 4 Kb.

class may also be the word all, in which case all classes are added to the appropriate list. (The effect of adding all classes to the included class list is to force full crash dumps under all circumstances. The effect of adding all classes to the excluded class list is to disable crash dumps.)

Persistent Dump Devices

To mark the dump devices as persistent, there are two configuration modes available.

config_crashconf_mode

In this mode crashconf (this command) and crashconf() (see crashconf(2)) are the only mechanisms available to mark dump devices as persistent. Logical volumes marked for dump using lvlnboot or vxvmboot and devices marked in /stand/system for dump will be ignored during boot-up. This is the preferred method for dump device configuration and will be used from this HP-UX release onwards. This mode can be enabled using the -s option. VxVM stores extent information of persistent dump logical volumes in lif (see lif(4)). Up to ten VxVM logical volumes can be marked persistent.

config_deprecated_mode

The logical volumes marked for dump using lvlnboot or vxvmboot and devices marked in /stand/system for dump will be configured as dump devices during boot-up. Devices marked as persistent, using crashconf -s, will be ignored during boot-up. Marking devices using lvlnboot, vxvmboot, and /stand/system will be obsoleted in the next HP-UX release. This mode is deprecated in this release and will be obsoleted in the next HP-UX release. This is the default mode for dump and can be enabled using the -o option also.

Persistent dump devices information is maintained in the kernel registry services, (KRS, see krs(5)).

Options

The following are valid options for crashconf:

-a

Apply the dump devices in /etc/fstab to the current list of crash dump devices:

add these devices to the current list; or
(with -d) delete them from the current list; or
(with -r) replace the current list.

This is in addition to the dump devices specified on the command line. See fstab(4) for information on the format of /etc/fstab.

-c cmode

Specify the compression mode: either ON or OFF. If the system is not able to identify enough processing resources to do compressed dump, a warning message will be issued.

-d

Delete all dump devices mentioned on the command line from the current list of crash dump devices. If the -a option is also specified, then dump devices in /etc/fstab will also be deleted. However, the dump device list cannot be made empty. This option cannot be used with the -r (replace) option.

-e classes

Add the specified classes to the list of excluded classes; or if -r is used, replace the list of excluded classes with the specified classes. If any of the specified classes are present in the current included class list, they will be removed from the included class list.

-i classes

Add the specified classes to the the list of included classes; or if -r is used, replace the list of included classes with the specified classes. If any of the specified classes are present in the current excluded class list, they will be removed from the excluded class list.

-l

Display the lunpath hardware path (see intro(7)) through which the device is currently configured. The lunpath hardware path is not displayed if the device is offline. This path may change in cases of path failover or device reconfiguration.

-o

Switch dump configuration mode from config_crashconf_mode to config_deprecated_mode. This option will be obsoleted in the next HP-UX release. The -o and -s options are mutually exclusive. The extent information for persistent VxVM dump logical volumes will continue to be present in lif (see lif(4)).

-p pmode

Specify the concurrency mode: either ON or OFF. Depending on the availability of additional memory and the configuration of dump devices, the system may fall back to non-concurrent dump mode and a warning message will be issued. Currently supported only on Integrity systems.

-r

Specify that any changes should replace, rather than add to, the current configuration. Thus, if devices or -a are specified, the current crash dump device list is replaced with new contents. Likewise, with -r, the -e and -i options replace the current class list. This option cannot be used with the -d option.

-s

Mark the dump device list as persistent across reboots. This will also enable the config_crashconf_mode. Use -o to switch back to config_deprecated_mode. The -s and -o options are mutually exclusive.

-t

When used with the -i, -e, -c, or -p options, set the dump tunables alwaysdump, dontdump, dump_compress_on, and dump_concurrent_on, respectively, to make the changes persistent across system reboots.

-v

Display the current crash dump configuration as well as the list of persistent dump devices. If any changes to the current configuration are specified on the same command line as -v, the configuration will be displayed after the requested changes are made.

RETURN VALUE

Upon exit, crashconf returns the following values:

0: Success.
1: The requested configuration changes could not be made.

WARNINGS

If the dump device configured goes offline, then that device will not be used for taking a crash dump. crashconf output displays whether the dump device is currently offline.

On systems running VxVM 3.5, the swap volumes to be configured for system crash dumps should be created with the usage type as swap during the creation of the swap volume. Not doing so will cause dump corruption. It is also possible to use the -U option of vxassist to create the swap volume correctly.

When attributes of a VxVM dump logical volume change, it should be re-configured using the crashconf command so that crash dump will use the updated values.

Marking dump devices using lvlnboot, vxvmboot, and /stand/system will be obsoleted in the next HP-UX release. The -s option of crashconf can be used to mark the dump device list as persistent.

The output of crashconf is not designed to be parsed by applications or scripts, but only to be read by humans. The output format may change without notice. Applications which require crash dump configuration information should retrieve that information using pstat.

Dump devices created by lvcreate must be contiguous (-Cy option) with bad block relocation turned off (-rn option).

AUTHOR

crashconf was developed by HP.