svcadm(8)을 검색하려면 섹션에서 8 을 선택하고, 맨 페이지 이름에 svcadm을 입력하고 검색을 누른다.
dumpadm(8)
dumpadm(8) System Administration Commands dumpadm(8)
NAME
dumpadm - configure operating system crash dump
SYNOPSIS
/usr/sbin/dumpadm [-enpuy] [-c content-spec] [-d dump-device]
[-m mink | minm | min%] [-s savecore-dir]
[-r root-dir] [-z on | off] [-D on | off]
DESCRIPTION
The dumpadm program is an administrative command that manages the con‐
figuration of the operating system crash dump facility. A crash dump is
a copy of the physical memory of the computer at the time of a fatal
system error. When a fatal operating system error occurs, a message de‐
scribing the error is printed to the console. If deferred dumping is
enabled (on), the operating system then generates a crash dump by pre‐
serving the contents of physical memory in RAM. If this is not possi‐
ble, or if deferred dumping is disabled (off), the contents of physical
memory are written to a predetermined dump device, which can be a ZFS
ZVOL, or a local disk partition.
Once the crash dump has been preserved, the system will reboot.
Fatal operating system errors can be caused by bugs in the operating
system, its associated device drivers and loadable modules, or by
faulty hardware. Whatever the cause, the crash dump itself provides in‐
valuable information to your support engineer to aid in diagnosing the
problem. As such, it is vital that the crash dump be retrieved and
given to your support provider. Following an operating system crash,
the savecore(8) utility is executed automatically during boot to re‐
trieve the crash dump and write it to your file system in compressed
form, to files named vmdump.X, and vmdump-<secname>.X, where X is an
integer identifying the dump. Afterward, savecore(8) can be invoked on
the same or another system to expand the compressed crash dump to files
named vmcore.X and vmcore-<secname>.X. The directory in which the crash
dump is saved on reboot can be configured using dumpadm command.
By default dedicated ZFS volumes are used for dump devices. For further
information about setting up a dump area with ZFS, see the Managing ZFS
File Systems in Oracle Solaris 11.4 book.
To view the current dump configuration, use the dumpadm command with no
arguments:
example# dumpadm
Dump content: kernel with ZFS metadata
Dump device: /dev/zvol/dsk/rpool/dump (dedicated)
Savecore directory: /var/crash
Savecore enabled: yes
Save compressed: on
Deferred Dump: on
When no options are specified, dumpadm displays the current crash dump
configuration. The example above shows the set of default values: the
dump content is set to kernel memory pages and ZFS metadata only. The
crash dump will be preserved in memory (if possible), else a dump de‐
vice will be used. The dump device is by default a zvol in the root
pool. The directory for savecore files is set to /var/crash/. savecore
is configured to run automatically on reboot and save the crash dump in
a compressed format.
When one or more options are specified, dumpadm verifies that your
changes are valid, and if so, reconfigures the crash dump parameters
and displays the resulting configuration. You must be root to view or
change dump parameters.
Upon system installation, dumpadm establishes a dump device of suffi‐
cient size, based on system memory size and other internal information,
to accommodate a dump file. If you subsequently attempt to create a
dump device that is too small to store the dump file, dumpadm issues a
warning message.
OPTIONS
The following options are supported:
-c content-spec
Modify the dump configuration so that the crash dump consists of
the specified dump content. The content-spec comprises of optional
content-type and content modifiers:
[ content-type ] [ +content-modifier | -content-modifier.. ]
content-type provides the basis, the content modifiers further
change the contents to be dumped. With +, the content modifiers
add extra data to be dumped, with - the data is left out.
The content-type can be one of the following:
kernel Kernel memory pages only. Note that this includes
only basic set of kernel pages, that is, not the
pages which can be specified with content modifiers.
all All memory pages. If all is specified, the system
image is written to the dump device. Note that the
resulting dump will include pages for filesystem
buffers.
curproc Kernel memory pages (as specified by 'kernel'), and
the memory pages of the process whose thread was
currently executing on the CPU on which the crash
dump was initiated. If the thread executing on that
CPU is a kernel thread not associated with any user
process, only kernel pages will be dumped.
allproc Kernel memory pages (as specified by 'kernel') and
all process pages. If allproc is specified, the sys‐
tem image is written to the dump device.
The content-modifier can be one of the following:
zfs Kernel pages which store ZFS metadata.
The content modifiers affect which portions of kernel memory
are dumped and which are not. They do not have any effect when
the 'all' content type is set.
If content-type is omitted, and only a content-modifier is
specified, then the currently configured content-type will re‐
main unchanged.
-d dump-device
Modify the dump configuration to use the specified dump device. The
dump device may one of the following:
dump-device
A block device specified as an absolute pathname, such as
/dev/dsk/cNtNdNsN, or a ZFS volume such as rpool/dump.
swap
If the special token swap is specified as the dump device,
dumpadm examines the active swap entries and selects the most
appropriate entry to configure as the dump device. See swap(8).
Refer to the NOTES below for details of the algorithm used to
select an appropriate swap entry.
Use of a single swap device for a dump device is not recom‐
mended for low memory systems. If the system has less than 8
gigabytes of RAM then it should have a dedicated swap device,
sufficient to allow the system to boot to the multi-user mile‐
stone, and a separate dump device which may also be used as an
additional swap device.
none
Do not use disk based dump device. The crash dump will still be
retrieved if it is possible to store crash dumps in memory.
-D on | off
Modify the dump configuration to control whether dumping is de‐
ferred or not. The options are on, to preserve the crash dump in
system memory if possible, and off, to write the crash dump to the
dump device as part of the panic process. After the system reboots,
savecore will find the crash dump in either system memory or on the
dump device, and copy it to the savecore directory at that time.
The default is on, because in most cases that will reduce the over‐
all downtime of the system.
-e
Print estimate of disk space required for storing compressed crash
dump. The value is computed using current configuration and cur‐
rently running system.
-m mink | minm | min%
Create a minfree file in the current savecore directory indicating
that savecore should maintain at least the specified amount of free
space in the file system where the savecore directory is located.
The min argument can be one of the following:
k
A positive integer suffixed with the unit k specifying kilo‐
bytes.
m
A positive integer suffixed with the unit m specifying
megabytes.
%
A % symbol, indicating that the minfree value should be com‐
puted as the specified percentage of the total current size of
the file system containing the savecore directory.
The savecore command will consult the minfree file, if present,
prior to writing the dump files. If the size of these files would
decrease the amount of free disk space below the minfree threshold,
no dump files are written and an error message is logged. The ad‐
ministrator should immediately clean up the savecore directory to
provide adequate free space, and re-execute the savecore command
manually. The administrator can also specify an alternate directory
on the savecore command-line.
-n
Modify the dump configuration to not run savecore automatically on
reboot. This is not the recommended system configuration.
savecore(8) can be run manually once the system has booted up to
extract the crash dump to the savecore directory.
If the dump device is a swap partition, the dump data may be over‐
written as the system begins to use the swap device. If savecore is
not executed shortly after boot, crash dump retrieval may not be
possible.
-p
Produce machine parseable output.
-r root-dir
Specify an alternate root directory relative to which dumpadm
should create files. If no -r argument is specified, the default
root directory / is used.
-s savecore-dir
Modify the dump configuration to use the specified directory to
save files written by savecore. The directory should be an absolute
path and exist on the system. If upon reboot the directory does not
exist, it will be created prior to the execution of savecore. See
the NOTES section below for a discussion of security issues relat‐
ing to access to the savecore directory. The default savecore di‐
rectory is /var/crash/.
-u
Forcibly update the kernel dump configuration based on the contents
of /etc/dumpadm.conf. Normally this option is used only on reboot
when starting svc:/system/dump:config, when the dumpadm settings
from the previous boot must be restored. Your dump configuration is
saved in the configuration file for this purpose. If the configura‐
tion file is missing or contains invalid values for any dump prop‐
erties, the default values are substituted. Following the update,
the configuration file is resynchronized with the kernel dump con‐
figuration.
-y
Modify the dump configuration to automatically run savecore on re‐
boot. This is the default for this dump setting. See NOTES.
-z on | off
Modify the dump configuration to control the operation of savecore
on reboot. The options are on, to enable saving core files in a
compressed format, and off, to automatically uncompress the crash
dump file. The default is on, because crash dump files can be very
large and require less file system space if saved in a compressed
format.
EXAMPLES
Example 1 Reconfiguring The Dump Device to store current process pages
and no ZFS metadata pages
example# dumpadm -c curproc-zfs
Dump content: kernel and current process without ZFS metadata
Dump device: /dev/zvol/dsk/rpool/dump (dedicated)
Savecore directory: /var/crash
Savecore enabled: yes
Save compressed: on
Deferred Dump: on
Example 2 Specifying allproc or all content
example# dumpadm -c all
Dump content: all
Dump device: /dev/zvol/dsk/rpool/dump (dedicated)
Savecore directory: /var/crash
Savecore enabled: yes
Save compressed: on
Deferred Dump: on
Example 3 Preserving crash dump if savecore is disabled
If savecore is disabled, the crash dump may still be preserved in mem‐
ory and copied to the dump device after reboot. It can be extracted
later by running savecore(8) manually.
example# dumpadm -n -c kernel+zfs
Dump content: kernel with ZFS metadata
Dump device: /dev/zvol/dsk/rpool/dump (dedicated)
Savecore directory: /var/crash
Savecore enabled: no
Save compressed: on
Deferred Dump: on
EXIT STATUS
The following exit values are returned:
0
Dump configuration is valid and the specified modifications, if
any, were made successfully.
1
A fatal error occurred in either obtaining or modifying the dump
configuration.
2
Invalid command line options were specified.
FILES
/dev/dump
Crash dump management device driver.
/etc/dumpadm.conf
Contains configuration parameters for dumpadm and savecore. Modifi‐
able only using dumpadm.
savecore-directory/minfree
Contains minimum amount of free space for savecore-directory. See
savecore(8).
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
tab() box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) ATTRIBUTE TYPEAT‐
TRIBUTE VALUE _ Availabilitysystem/core-os
SEE ALSO
svcs(1), uname(1), attributes(7), smf(7), savecore(8), svcadm(8),
swap(8)
NOTES
The system crash dump service is managed by the service management fa‐
cility, smf(7), under the following service identifiers:
svc:/system/dump:config
svc:/system/dump:deferred
svc:/system/dump:disk
svc:/system/dump:swap
While administrative actions on this service, such as enabling, dis‐
abling, or requesting restart, can be performed using svcadm(8), it is
not recommended to disable these services. The status of these services
can be queried using the svcs(1) command.
Dump Device Selection
When the special swap token is specified as the argument to dumpadm -d
the utility will attempt to configure the most appropriate swap device
as the dump device. dumpadm configures the largest swap block device as
the dump device; if no block devices are available for swap, the
largest swap entry is configured as the dump device. If no swap entries
are present, or none can be configured as the dump device, a warning
message will be displayed.
Dump Device/Swap Device Interaction
In the event that the dump device is also a swap device and the swap
device is deleted by the administrator using the swap -d command, the
swap command will automatically invoke dumpadm -d swap in order to
attempt to configure another appropriate swap device as the dump de‐
vice. If no swap devices remain or none can be configured as the dump
device, the crash dump will be disabled and a warning message will be
displayed. Similarly, if the crash dump is disabled and the administra‐
tor adds a new swap device using the swap -a command, dumpadm -d
swap will be invoked to re-enable the crash dump using the new swap de‐
vice.
Once dumpadm -d swap has been issued, the new dump device is stored
in the configuration file or kvol_dump ZFS property for subsequent re‐
boots. If a larger or more appropriate swap device is added by the ad‐
ministrator, the dump device is not changed; the administrator must re-
execute dumpadm -d swap to reselect the most appropriate device from
the new list of swap devices.
Minimum Free Space
If the dumpadm -m option is used to create a minfree file based on a
percentage of the total size of the file system containing the savecore
directory, this value is not automatically recomputed if the file sys‐
tem subsequently changes size. In this case, the administrator must re-
execute dumpadm -m to recompute the minfree value. If no such file ex‐
ists in the savecore directory, savecore will default to a free space
threshold of one megabyte. If no free space threshold is desired, a
minfree file containing size 0 can be created.
If there is insufficient space in the dump directory, and system pre‐
served a crash dump image in memory, then the image is written to the
dump device for later extraction using savecore(8).
Security Issues
If, upon reboot, the specified savecore directory is not present, it
will be created prior to the execution of savecore with permissions
0700 (read, write, execute by owner only) and owner root. It is recom‐
mended that alternate savecore directories also be created with similar
permissions, as the operating system crash dump files themselves may
contain secure information.
Default for savecore
System installation software might reserve a dedicated dump device (for
example, a disk slice or a ZFS volume). In such a case, the dumpadm de‐
fault can be set to -n, meaning that savecore does not run automati‐
cally when the system reboots. A crash image will be preserved on the
dump device even if initially it was preserved in memory. Run
/usr/bin/savecore manually as root to retrieve the crash image and copy
it to set of files under /var/crash. The crash image will remain on the
dump device until overwritten by a later one.
Oracle Solaris 11.4 25 February 2023 dumpadm(8)