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RESIZE_FFS(8) NetBSD System Manager's Manual RESIZE_FFS(8)
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resize_ffs -- resize a file system on disk or in a file
resize_ffs [-cpvy] [-s size] special
resize_ffs resizes a file system. special is the name of the raw disk
device or file where the file system resides. resize_ffs can both grow
and shrink file systems. When growing, the disk device must of course be
large enough to contain the new file system; resize_ffs simply extends
the file system data structures into the new space. When shrinking,
resize_ffs assumes this. resize_ffs has to copy anything that currently
resides in the space being shrunk away; there must be enough space free
on the file system for this to succeed. If there is not, resize_ffs will
complain and exit; when this happens, it attempts to always leave the
file system in a consistent state, but it is probably a good idea to
check the file system with fsck(8).
If no -s option is provided, resize_ffs will grow the file system to the
underlying device size which is determined from special.
The options are as follows:
-c Check to see if the new size would change the file system. No
changes will be made to the file system.
-p Display a progress meter during the resize process.
-s Specify the file system size to which the file system should be
resized. The size is given as the count of disk sectors, usually
512 bytes. It will not work correctly for file systems with
other sector sizes. To see the exact value, have a look at the
disk specification or the disklabel. Mostly used to shrink file
-v Be more verbose.
-y Disable sanity questions made by resize_ffs.
Interrupting resize_ffs may leave your file system in an inconsistent
state and require a restore from backup. It attempts to write in the
proper order to avoid problems, but as it is still considered experimen-
tal, you should take great care when using it.
When resize_ffs is applied to a consistent file system, it should always
produce a consistent file system; if the file system is not consistent to
start with, resize_ffs may misbehave, anything from dumping core to com-
pletely curdling the data. It is probably wise to fsck(8) the file sys-
tem before and after, just to be safe. You should be aware that just
because fsck(8) is happy with the file system does not mean it is intact.
resize_ffs exits with 0 on success. Any major problems will cause
resize_ffs to exit with the non-zero exit(3) codes, so as to alert any
invoking program or script that human intervention is required.
will enlarge the file system on the Logical Volume /dev/vg00/lv1 from
Volume Group vg00 to the current device size.
fs(5), fsck(8), newfs(8)
The resize_ffs command first appeared in NetBSD 2.0.
der Mouse <firstname.lastname@example.org> (primary author)
Jeff Rizzo <riz@NetBSD.org> (Byteswapped file system and UFS2 support)
A big bug-finding kudos goes to John Kohl for finding a significant rota-
tional layout bug.
Can fail to shrink a file system when there actually is enough space,
because it does not distinguish between a block allocated as a block and
a block fully occupied by two or more frags. This is unlikely to occur
in practice; except for pathological cases, it can happen only when the
new size is extremely close to the minimum possible.
Has no intelligence whatever when it comes to allocating blocks to copy
data into when shrinking.
Does not currently support shrinking FFSv2 file systems.
NetBSD 9.3 October 1, 2017 NetBSD 9.3