| RESIZE_FFS(8) | System Manager's Manual | RESIZE_FFS(8) | 
resize_ffs —
| resize_ffs | [ -cpvy] [-ssize] 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-p-s-v-yresize_ffs.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 experimental,
  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 completely curdling the data.
    It is probably wise to fsck(8)
    the file system 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.
resize_ffs
  /dev/vg00/rlv1will enlarge the file system on the Logical Volume /dev/vg00/lv1 from Volume Group vg00 to the current device size.
resize_ffs command first appeared in
  NetBSD 2.0.
A big bug-finding kudos goes to John Kohl for finding a significant rotational layout bug.
Has no intelligence whatever when it comes to allocating blocks to copy data into when shrinking.
Does not currently support shrinking FFSv2 file systems.
| October 1, 2017 | NetBSD 9.4 |