Man pages › Compared with Linux and the BSDs

`savecore(8)` on Solnix vs Linux and the BSDs

On Solnix, savecore is the illumos /usr/bin/savecore, run at boot by the dumpadm SMF service. It saves either a compressed vmdump.n or an uncompressed vmcore.n plus unix.n, depending on the dumpadm configuration. Unlike the BSDs, it has no -c (clear dump) and no -N (kernel path) option.

The manual pages

Solnix: savecore(8) from pkgs.solnix.illumos-world-man · illumos.org
FreeBSD: savecore(8) 15.1-RELEASE
OpenBSD: savecore(8) 8.0
NetBSD: savecore(8) 11.0

What Solnix runs

A default Solnix system runs the illumos savecore at /usr/bin/savecore. No other variants are shipped. The dump directory and compression behaviour are configured with dumpadm(8), and the service is svc:/system/dumpadm:default.

Differences

Compared with	Topic	What differs
FreeBSD, OpenBSD, NetBSD	how savecore is started at boot	On Solnix, the dumpadm SMF service (svc:/system/dumpadm:default) invokes savecore at each boot. The BSD pages say savecore is meant to be called from `/etc/rc` (FreeBSD, OpenBSD) or from rc(8) before swapping is enabled (NetBSD). Source: Solnix savecore(8) DESCRIPTION, NOTES; FreeBSD savecore(8) DESCRIPTION; OpenBSD savecore(8) DESCRIPTION; NetBSD savecore(8) DESCRIPTION
FreeBSD, OpenBSD, NetBSD	output file names	Solnix writes directory/vmdump.n (compressed) or directory/vmcore.n plus directory/unix.n. FreeBSD writes vmcore.# and info.#. OpenBSD writes bsd.#.core and bsd.#. NetBSD writes netbsd.#.core and netbsd.#. Source: Solnix savecore(8) DESCRIPTION; FreeBSD savecore(8) DESCRIPTION; OpenBSD savecore(8) DESCRIPTION; NetBSD savecore(8) DESCRIPTION
FreeBSD, OpenBSD, NetBSD	numbering of saved dumps	Solnix replaces n with a number that grows each run in that directory; the page does not mention a bounds file. FreeBSD, OpenBSD and NetBSD take # from the first line of directory/bounds and write it back after each successful run. Source: Solnix savecore(8) DESCRIPTION; FreeBSD/OpenBSD/NetBSD savecore(8) DESCRIPTION (bounds)
FreeBSD, OpenBSD, NetBSD	`-c` (clear the dump)	Solnix savecore has no `-c` option. FreeBSD, OpenBSD and NetBSD `-c` clears the dump so later runs ignore it. On Solnix, `-d` does the reverse: it makes savecore save a dump even if the header says it was already saved. Source: Solnix savecore(8) SYNOPSIS, -d; FreeBSD savecore(8) -c; OpenBSD savecore(8) -c; NetBSD savecore(8) -c
FreeBSD, OpenBSD, NetBSD	`-f` meaning	Solnix `-f` takes a dumpfile argument and reads the dump from that file instead of the dump device, for example a copy made with dd(8). On FreeBSD, OpenBSD and NetBSD, `-f` takes no argument and forces a dump to be taken despite a bad or cleared dump. Source: Solnix savecore(8) -f dumpfile; FreeBSD savecore(8) -f; OpenBSD savecore(8) -f; NetBSD savecore(8) -f
FreeBSD	`-L` live dump	Solnix `-L` saves a live snapshot to the dump device, then writes it to files in the directory. It needs a dedicated dump device set up with dumpadm(8). The result is not fully self-consistent. FreeBSD `-L` also dumps the running system, and can be combined with `-f`, `-v`, `-Z`, `-z` and `-m`. Source: Solnix savecore(8) -L; FreeBSD savecore(8) SYNOPSIS, -L
FreeBSD, OpenBSD, NetBSD	compression options	Solnix has no `-z` or `-Z`. Whether the saved dump is compressed follows the dumpadm(8) configuration. FreeBSD has `-z` (gzip) and `-Z` (zstd, with `-L` only). OpenBSD and NetBSD have `-z`. NetBSD `-Z` level sets the gzip level. Source: Solnix savecore(8) DESCRIPTION; FreeBSD savecore(8) -z, -Z; OpenBSD savecore(8) -z; NetBSD savecore(8) -z, -Z level
OpenBSD, NetBSD	kernel selection (`-N`)	Solnix has no `-N`. OpenBSD and NetBSD `-N` system names the kernel to save instead of the default (/bsd on OpenBSD; the getbootfile(3) result on NetBSD). The Solnix page saves the kernel namelist as unix.n and does not document choosing it. Source: OpenBSD savecore(8) -N; NetBSD savecore(8) -N; Solnix savecore(8) DESCRIPTION
FreeBSD, NetBSD	checking whether a dump exists	Solnix has no option to test for a dump. FreeBSD `-C` exits 0 if a dump exists and 1 if not. NetBSD `-n` exits 0 if a dump is present, non-zero otherwise. Source: FreeBSD savecore(8) -C; NetBSD savecore(8) -n; Solnix savecore(8) OPTIONS
FreeBSD, OpenBSD, NetBSD	default directory and device selection	With no directory, Solnix uses the default savecore directory set by dumpadm(8). FreeBSD uses the current directory and NetBSD uses `/var/crash.` OpenBSD requires a directory in its synopsis. FreeBSD also accepts device arguments; Solnix has none. Source: Solnix savecore(8) OPERANDS; FreeBSD savecore(8) DESCRIPTION; NetBSD savecore(8) DESCRIPTION; OpenBSD savecore(8) SYNOPSIS
FreeBSD, OpenBSD, NetBSD	minfree default	Solnix assumes a minfree of 1 megabyte when directory/minfree does not exist. The BSD pages describe only the case where the file exists and give no default. Solnix does not say it checks free space before copying. Source: Solnix savecore(8) DESCRIPTION; FreeBSD/OpenBSD/NetBSD savecore(8) DESCRIPTION (minfree)
FreeBSD, OpenBSD, NetBSD	`-r` read-only recovery	Solnix `-r` opens the dump device or file read-only and changes nothing, so a dump can be recovered from a read-only device. It cannot be combined with `-L`. The BSD pages document no equivalent. Source: Solnix savecore(8) -r; FreeBSD/OpenBSD/NetBSD savecore(8) OPTIONS

Standards

POSIX: savecore is not a POSIX.1-2024 utility.

Writing portable scripts

Do not script against savecore options across systems: -f, -c, -L and -z mean different things or are missing. Branch on the OS and use that system's own flags.
Do not hard-code dump file names. Solnix writes vmcore.n and vmdump.n, while the BSDs write vmcore.#, bsd.#.core or netbsd.#.core.

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.