dumpadm(8) on Solnix vs Linux and the BSDs
dumpadm is the illumos command at /usr/sbin/dumpadm that configures the crash dump device, dump content, savecore directory and compression, and prints the current configuration when run with no options. FreeBSD dumpon, and OpenBSD and NetBSD savecore, cover only parts of this job.
The manual pages
- Solnix: dumpadm(8) from
pkgs.solnix.illumos-world-man· illumos.org - FreeBSD: dumpon(8) 15.1-RELEASE (different command, similar job)
- OpenBSD: savecore(8) 8.0 (different command, similar job)
- NetBSD: savecore(8) 11.0 (different command, similar job)
What Solnix runs
A default Solnix system runs the illumos dumpadm at /usr/sbin/dumpadm. No other variants are shipped. The page says savecore(8) runs automatically at boot to retrieve the dump unless -n was set. The bundle does not include the Solnix savecore(8) text.
Differences
| Compared with | Topic | What differs |
|---|---|---|
| FreeBSD, OpenBSD, NetBSD | scope of the command | Solnix dumpadm sets the dump device, content type, savecore directory, minfree and compression, and shows the configuration. FreeBSD dumpon only selects dump devices. OpenBSD and NetBSD savecore only copy an existing dump out of the dump area. Source: Solnix dumpadm(8) DESCRIPTION, OPTIONS; FreeBSD dumpon(8) DESCRIPTION; OpenBSD savecore(8) DESCRIPTION; NetBSD savecore(8) DESCRIPTION |
| FreeBSD | persistent configuration | Solnix keeps the dump configuration in /etc/dumpadm.conf, and -u restores it at boot via svc:/system/dumpadm:default. FreeBSD dumpon is normally made persistent through the rc.conf(5) variables dumpdev and dumpon_flags.Source: Solnix dumpadm(8) -u; FreeBSD dumpon(8) DESCRIPTION |
| FreeBSD | showing the current device | Solnix dumpadm with no arguments prints content, device, savecore directory, savecore enabled and compression. FreeBSD uses dumpon -l, which lists only the configured dump devices, or /dev/null if there are none.Source: Solnix dumpadm(8) DESCRIPTION; FreeBSD dumpon(8) -l |
| FreeBSD | disabling dumps | Solnix uses dumpadm -d none to remove the active dump device. FreeBSD uses dumpon off to remove all devices, or dumpon -r to remove a single device from its fallback list.Source: Solnix dumpadm(8) -d none; FreeBSD dumpon(8) SYNOPSIS, -r |
| FreeBSD | -z meaning | Solnix dumpadm -z takes on or off and controls whether the dump is compressed. The page says compression is on by default. FreeBSD dumpon -z takes no argument and enables gzip, and -Z enables Zstandard.Source: Solnix dumpadm(8) SYNOPSIS, DESCRIPTION; FreeBSD dumpon(8) -z, -Z |
| OpenBSD, NetBSD | -z meaning and saved file names | On OpenBSD and NetBSD, savecore -z is a flag that compresses the saved dump and kernel, and the files are bsd.# or netbsd.# with a core suffix. On Solnix, compression defaults to on and savecore writes vmdump.X; with it off, it writes unix.X and vmcore.X.Source: Solnix dumpadm(8) DESCRIPTION; OpenBSD savecore(8) -z; NetBSD savecore(8) -z |
| FreeBSD, OpenBSD, NetBSD | dump content | Solnix -c chooses kernel, all, or curproc pages. FreeBSD defaults to mini dumps, with full dumps selected by the debug.minidump sysctl. The OpenBSD and NetBSD pages describe no content selection.Source: Solnix dumpadm(8) -c; FreeBSD dumpon(8) Minidumps; OpenBSD savecore(8); NetBSD savecore(8) |
| FreeBSD, OpenBSD, NetBSD | default dump device | With a UFS root, Solnix defaults the dump device to a swap partition; with a ZFS root it uses dedicated ZFS volumes for swap and dump. A ZFS volume cannot be both swap and dump device. NetBSD says the dump area is typically in swap. The OpenBSD and FreeBSD pages state no default. Source: Solnix dumpadm(8) DESCRIPTION, -d swap; NetBSD savecore(8) DESCRIPTION; FreeBSD dumpon(8) |
| FreeBSD | netdump and encrypted dumps | FreeBSD dumpon can dump to a netdumpd(8) server (-s, -c, -g) and encrypt dumps (-k, -C). The Solnix dumpadm page shows no network or encrypted dump option.Source: FreeBSD dumpon(8) Netdump, -k, -C; Solnix dumpadm(8) SYNOPSIS |
| OpenBSD, NetBSD | where savecore puts dumps | Solnix sets the savecore directory with dumpadm -s, default /var/crash/hostname, creating it at reboot if missing. OpenBSD savecore requires a directory argument. NetBSD defaults to /var/crash.Source: Solnix dumpadm(8) -s; OpenBSD savecore(8) SYNOPSIS; NetBSD savecore(8) DESCRIPTION |
| OpenBSD, NetBSD | minfree | Solnix dumpadm -m writes a minfree file in the savecore directory, in k, m or % units. OpenBSD and NetBSD savecore read directory/minfree, whose first line is a number of kilobytes; neither page has an option to write it.Source: Solnix dumpadm(8) -m; OpenBSD savecore(8) DESCRIPTION; NetBSD savecore(8) DESCRIPTION |
| NetBSD | checking for a dump | NetBSD savecore -n exits zero if a dump is present, and -c clears it. The Solnix dumpadm page documents neither; it has -e to estimate the dump size for the running system.Source: NetBSD savecore(8) -n, -c; Solnix dumpadm(8) -e |
Everyday tasks
| Task | Solnix | FreeBSD | OpenBSD | NetBSD |
|---|---|---|---|---|
| show current crash dump configuration | dumpadm | dumpon -l | — | — |
| set the dump device | dumpadm -d dump-device | dumpon device | — | — |
| disable crash dumps | dumpadm -d none | dumpon off | — | — |
| save the dump after reboot | savecore runs automatically at boot (savecore(8)) | — | savecore directory | savecore [directory] |
| set where dumps are saved | dumpadm -s savecore-dir | — | savecore directory | savecore directory |
| compress saved dumps | dumpadm -z on | dumpon -z (gzip) or -Z (Zstandard) | savecore -z | savecore -z |
| clear a dump without saving it | — | — | savecore -c | savecore -c |
| estimate dump size | dumpadm -e | — | — | — |
Standards
- POSIX: dumpadm is not a POSIX.1-2024 utility.
Writing portable scripts
- Do not script dumpadm against the BSDs: configuration is dumpadm and
/etc/dumpadm.confon Solnix, dumpon with rc.conf(5) dumpdev on FreeBSD, and savecore at boot from rc(8) on OpenBSD and NetBSD. - Do not assume saved dump file names: Solnix writes vmdump.X (or unix.X and vmcore.X), while OpenBSD and NetBSD write bsd.# or netbsd.# with a core suffix.
Every difference here is taken from the manual pages linked above: Solnix's published page, Linux (man-pages and the GNU and util-linux manuals), FreeBSD, OpenBSD and NetBSD. Each row names its source. Where a manual is silent, this page is too. Compiled 2026-10-26. Found a mistake? Mail hackers@lists.solnix.io.