GROWFS(8) BSD System Manager's Manual GROWFS(8)
growfs - grow size of an existing ffs filesystem
growfs [-Ny] [-s size] special
The growfs utility extends the newfs(8) program. Before starting growfs
the slice must be labeled to a bigger size using disklabel(8). If you
wish to grow a filesystem beyond the boundary of the partition it resides
in, you must re-size the partition using fdisk(8) before running growfs.
The growfs utility extends the size of the filesystem on the specified
special file.
Currently growfs can only enlarge unmounted filesystems. Do not try en-
larging a mounted filesystem - your system may panic and you will not be
able to use the filesystem any longer. Most of the newfs(8) options can-
not be changed by growfs . In fact, you can only increase the size of the
filesystem. Use tunefs(8) for other changes.
The following options are available:
-N Test mode. Causes the new filesystem parameters to be printed
out without actually enlarging the filesystem.
-s size Determines the size of the filesystem after enlarging in sec-
tors. This value defaults to the size of the raw partition
specified in special (in other words, growfs will enlarge the
filesystem to the size of the entire partition).
-y Expert mode. Usually growfs will ask you if you have taken a
backup of your data and will test whether special is currently
mounted. The -y flag suppresses this, so use this option with
great care!
growfs -s 4194304 /dev/rwd0f
will enlarge /dev/rwd0f up to 2GB if there is enough space in /dev/rwd0f.
The growfs utility works starting with FreeBSD 3.x. There may be cases on
FreeBSD 3.x only, when growfs does not recognize properly whether or not
the filesystem is mounted and exits with an error message ("nothing
done"). Then please use growfs -y if you are sure that the filesystem is
not mounted. The growfs utility has not yet been tested on OpenBSD at
all, and not much on MirBSD. They behave like FreeBSD 3.x in the respect
shown above. It is also recommended to always use fsck(8) before and
after enlarging (just to be on the safe side).
For enlarging beyond certain limits, it is essential to have some free
blocks available in the first cylinder group. If that space is not avail-
able in the first cylinder group, a critical data structure has to be re-
located into one of the new available cylinder groups. On FreeBSD 3.x
this will cause problems with fsck(8) afterwards. So fsck(8) needs to be
patched if you want to use growfs for FreeBSD 3.x. This patch is already
integrated in FreeBSD starting with FreeBSD 4.4. To avoid an unexpected
relocation of that structure it is possible to use ffsinfo -g 0 on the
first cylinder group to verify that nbfree in the CYLINDER SUMMARY
(internal cs) of the CYLINDER GROUP cgr0 has enough blocks. As a rule of
thumb for default filesystem parameters one block is needed for every 2
GB of total filesystem size.
Normally growfs writes this critical structure to disk and reads it again
later for doing more updates. This read operation will provide unexpected
data when using -N. Therefore, this part cannot really be simulated and
will be skipped in test mode.
disklabel(8), dumpfs(8), fdisk(8), ffsinfo(8), fsck(8), newfs(8),
tunefs(8)
The growfs utility first appeared in FreeBSD 4.4.
Christoph Herrmann <chm@FreeBSD.org>
Thomas-Henning von Kamptz <tomsoft@FreeBSD.org>
The GROWFS team <growfs@Tomsoft.COM>
It is recommended to always use fsck(8) after enlarging (just to be on
the safe side).
MirBSD #10-current September 8, 2000 1