By default, the primary swap device also serves as a dump
area when no other dump area is specifically designated. Although
you are not required to retain primary swap as your dump area, doing
so will conserve disk space. You can configure a different or multiple
dump devices on your system. To do this, you will need to create
a logical volume (or disk section) as a dump device. This device
can also be used, if you wish, for swap.
How Much Disk Space Should Be Used for Dump? |
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The amount of disk space made available for core dumps should
accommodate your system's physical (core) memory. (If you need to
determine the amount of physical memory on your system, see "Estimating
Your Swap Space Needs" earlier in this chapter.)
Because the physical memory on your system may exceed the
space available in the primary swap area, you may wish to configure
additional disk space for the full core memory image. Otherwise,
only a partial core image will be saved which may not be sufficient
for analyzing problems.
Configuring Dump Using HP-UX Commands |
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If you do not use SAM to configure your dump areas, you should
follow the guidelines below.
Although dump areas can be configured within disk sections,
it is preferable to use logical volumes.
A dump logical volume can exist only within the root volume
group, that is, the volume group that contains the root logical
volume.
To create a dump logical volume, you first use the lvcreate
command. You must set a contiguous allocation policy using the -C y
option and specify no bad block relocation using -r n.
See lvcreate(1M) for more information.
When configuring a logical volume as a dump device, you must
next use lvlnboot(1M) with the -d
option to update the BDRA (Boot Data Reserved Area). The BDRA maintains
the information that the kernel requires about each bootable disk
within the root volume group.
Suppose, for example, you have created a logical volume /dev/vg00/lvol2
for use as a dump area.
To update the boot information, enter:
lvlnboot -d lvol2 /dev/vg00 |
It is possible to use any secondary swap logical volume as
a dump area as well, provided the swap area is in the root volume
group.
To discontinue the use of a currently configured logical volume
as a dump device, you use lvrmboot(1M) also
with the -d option.
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 | CAUTION: To prevent possible file corruption, a dump logical
volume (or a swap logical volume used for dump) must lie within
the first two GB on the physical volume. The lvlnboot
command will not allow a dump logical volume to be configured that
exceeds two GB (but it will allow such a swap logical volume to
be so configured). |
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Before the above changes to the BDRA take effect, you must
either add (in the case of lvlnboot)
or remove (in the case of lvrmboot)
the following line within the system configuration file (/stand/system
by default) and then reconfigure the kernel:
For more information on the system configuration file, see
config(1M).
After reconfiguring the kernel, you must reboot the system.
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