growfs(8)

NAME

growfs - grow size of an existing ufs file system

SYNOPSIS

growfs [-Ny] [-s size] special

DESCRIPTION

The growfs utility extends the newfs(8) program. Before

starting growfs
the disk must be labeled to a bigger size using bsdlabel(8).

If you wish
to grow a file system beyond the boundary of the slice it

resides in, you
must re-size the slice using fdisk(8) before running growfs.

If you are
using volumes you must enlarge them by using vinum(8). The

growfs utility extends the size of the file system on the specified

special file.
Currently growfs can only enlarge unmounted file systems.

Do not try
enlarging a mounted file system, your system may panic and

you will not
be able to use the file system any longer. Most of the

newfs(8) options
cannot be changed by growfs. In fact, you can only increase

the size of
the file system. Use tunefs(8) for other changes.

The following options are available:

-N ``Test mode''. Causes the new file system parame

ters to be

printed out without actually enlarging the file sys

tem.

-y ``Expert mode''. Usually growfs will ask you if you

took a

backup of your data before and will do some tests

whether special
is currently mounted or whether there are any active

snapshots on
the file system specified. This will be suppressed.

So use this
option with great care!

-s size

Determines the size of the file system after enlarg

ing in sectors. This value defaults to the size of the raw

partition specified in special (in other words, growfs will en

large the file
system to the size of the entire partition).

EXAMPLES

growfs -s 4194304 /dev/vinum/testvol

will enlarge /dev/vinum/testvol up to 2GB if there is enough

space in
/dev/vinum/testvol.

SEE ALSO

bsdlabel(8), dumpfs(8), fdisk(8), ffsinfo(8), fsck(8),

newfs(8),
tunefs(8), vinum(8)

HISTORY

The growfs utility first appeared in FreeBSD 4.4.

AUTHORS

Christoph Herrmann <chm@FreeBSD.org>
Thomas-Henning von Kamptz <tomsoft@FreeBSD.org>
The GROWFS team <growfs@Tomsoft.COM>

BUGS

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 file system is mounted and exits with an error mes

sage. Then
please use growfs -y if you are sure that the file system is

not mounted.
It is also recommended to always use fsck(8) 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
available in the first cylinder group, a critical data

structure has to
be relocated 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 -l 4 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 file system parameters one block

is needed for
every 2 GB of total file system size.

Normally growfs writes this critical structure to disk and

reads it again
later for doing more updates. This read operation will pro

vide unexpected data when using -N. Therefore, this part cannot re

ally be simulated and will be skipped in test mode.

BSD September 8, 2000

BSD