Compressed Dump

Compressed Dump White Paper, Version 1.3

page 10

Conﬁguration changes made using crashconf() take effect immediately and remain

in effect until the next system reboot, or until changed with a subsequent call to

crashconf().

Parameters

operation is a bitmask specifying what crashconf() should do. It must have at least

one of the following ﬂags set:

• DC_INCLUDE crashconf() will change the contents of the included class list. The

includeClasses parameter is valid.

• DC_EXCLUDE crashconf() will change the contents of the excluded class list.

The excludeClasses parameter is valid.

• DC_DEVICES crashconf() will change the contents of the crash dump device list.

The deviceCount, devices and deviceReturn parameters are valid.

• DC_SETCOMPRESS crashconf() will set the compression mode ON.

• DC_SETNOCOMPRESS crashconf() will set the compression mode OFF.

operation may also have the following ﬂag set:

• DC_REPLACE Changes to any of the lists will replace the current contents of

those lists. Without this ﬂag, changes will add to the current contents of those

lists.

includeClasses is a bitmask of classes that must be dumped. If it is set to DT_ALL,

all dumps will be full dumps. Other allowed values are described under Classes,

below.

excludeClasses is a bitmask of classes that may not be dumped unless a full dump

is required (due to the cause of the dump, or by explicit operator request). If it is set

to DT_ALL, dumps will be disabled. Other allowed values are described under

Classes, below.

devices is an array of deviceCount pathnames of block device ﬁles for crash dump

devices. To be valid, a device must be accessible and must not contain a ﬁle sys-

tem. Where LVM partitions are in use, the device number must be for a partition, not

the physical disk that contains it, and must represent a partition that is strictly contig-

uous on the physical disk. (LVM bad-block reallocation, and striping features may

not be in use on the partition.) Depending on the disk type, the dump space may be

restricted to the ﬁrst 2GB or 4GB of the physical disk.

deviceReturn is an array of deviceCount integers for returning the results of attempt-

ing to conﬁgure the corresponding device from the devices array. Upon return, each

element is set to a numeric value indicating the result of conﬁguring the correspond-

ing device as follows:

0 Successfully conﬁgured the corresponding device as a dump

device.

< 0 Failed to conﬁgure the corresponding device as a dump device.

The absolute value of the returned number can be used as an