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resize_ffs(8) [netbsd man page]

RESIZE_FFS(8)						    BSD System Manager's Manual 					     RESIZE_FFS(8)

NAME

     resize_ffs -- resize a file system on disk or in a file

SYNOPSIS

     resize_ffs [-y] [-s size] special

DESCRIPTION

     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 isn't,
     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:

     -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 speci-
	     fication or the disklabel.  Mostly used to shrink file systems.

     -y      Disable sanity questions made by resize_ffs.

WARNING

     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 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 consis-
     tent to start with, resize_ffs may misbehave, anything from dumping core to completely curdling the data.	It's 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.

EXIT STATUS

     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.

EXAMPLES

	   resize_ffs /dev/vg00/rlv1

     will enlarge the file system on the Logical Volume /dev/vg00/lv1 from Volume Group vg00 to the current device size.

SEE ALSO

     fs(5), fsck(8), newfs(8)

HISTORY

     The resize_ffs command first appeared in NetBSD 2.0.

AUTHORS

     der Mouse <mouse@rodents.montreal.qc.ca> (primary author)
     Jeff Rizzo <riz@NetBSD.org> (Byteswapped file system and UFS2 support)

     A big bug-finding kudos goes to John Kohl for finding the rotational layout bug referred to in the WARNING section above.

BUGS

     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.

     Doesn't currently support shrinking FFSv2 file systems.

BSD
								  January 4, 2011							       BSD

Check Out this Related Man Page

extendfs(8)						      System Manager's Manual						       extendfs(8)

NAME

       extendfs - Extends UFS file systems

SYNOPSIS

       /sbin/extendfs [- s] [disk_blocks]  device_name

DESCRIPTION

       Use  the  extendfs  command  to increase the storage space in a UFS file system.  The file system must not be mounted when you perform this
       operation.  To extend a mounted (in use) UFS file system, use the mount command with the -o extend option.

       The procedure for increasing the storage space of a UFS file system is as follows: Look at the contents the /etc/fstab file to identify the
       disk  partition that maps to the file system.  Ensure that there is available storage space on the target disk as follows: If LSM is in use
       on your system, use LSM commands to increase the size of the LSM volume as described in the Logical Storage Manager guide.  If LSM  is  not
       in use on your system, use the disklabel command or the diskconfig graphical user interface to check the current size and use of partitions
       on the disk.  If there is adequate space on an adjacent partition, use the disklabel command to write the current label to a file  as  fol-
       lows:  #  disklabel  -r	dsk4  > d4label Edit the disklabel file to change the size of the partition on which your UFS file system resides.
       Increase the number of disk blocks on the partition and decrease the disk block size of the adjacent partition  by  an  equivalent  number.
       Use the disklabel command with the -R option to write the revised label to the raw disk as follows: #  disklabel -R /dev/rdisk/dsk4 d4label
       When the disk label is revised, extend the file system using the extendfs command.  You can either use the full extent of the  newly  sized
       partition or extend the file system in stages.  The following example commands show both methods.  To extend the file system to use all the
       available space, you specify the disk partition on which the file system resides, as follows: #	extendfs  /dev/disk/dsk4g  To  extend  the
       file system to use only part of the available space, you specify a number of disk blocks, as follows: #	extendfs -s 300000 /dev/disk/dsk4g

	      The remainder of the extended partion is reserved for future use.

       You  can  extend a file system as many times as necessary, up to the physical limit of the storage device.  When no more space is available
       on the storage device, you must back up the file system using the dump command and restore the file system to a	storage  device  that  has
       more available space.

       Once  you  have extended a file system, the operation cannot be reversed except by a back up and restore operation. Use the dump command to
       back up the file system.  You can then reset the partition sizes manually and restore the file system to the storage device.

ERRORS

       The disklabel command produces output similar to that of the newfs command. If a list of disk blocks is not displayed on the terminal,  the
       command has failed.  Verify the partition settings and the mount status of the target file system.

       The  disklabel  command	does  not  permit you to overwrite a partition if it is in use.  Refer to the disklabel(8) reference page for more
       information on label errors.

FILES

       Specifies the command path.

RELATED INFORMATION

       diskconfig(8), disklabel(8), mount(8), and fstab(4).

																       extendfs(8)
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