FSIRAND(8)              OpenBSD System Manager's Manual             FSIRAND(8)

NAME
     fsirand - randomize inode generation numbers

SYNOPSIS
     fsirand [-bfp] special ...

DESCRIPTION
     The fsirand command installs random generation numbers on all the inodes
     for each filesystem specified on the command line by special.  This in-
     creases the security of NFS-exported filesystems by making it difficult
     to ``guess'' filehandles.

     Note: newfs(8) now does the equivalent of fsirand itself so it is no
     longer necessary to run fsirand by hand on a new filesystem.  It is only
     used to re-randomize or report on an existing filesystem.

     fsirand should only be used on an unmounted filesystem that has been
     checked with fsck(8) or a filesystem that is mounted read-only.  fsirand
     may be used on the root filesystem in single-user mode but the system
     should be rebooted via ``reboot -n'' afterwards.

     The options are as follows:

     -b      Use the default block size (usually 512 bytes) instead of the
             value gleaned from the disklabel.

     -f      Force fsirand to run even if the filesystem on special is not
             marked as clean.

     -p      Print the current generation numbers for all inodes instead of
             generating new ones.

SEE ALSO
     fs(5), fsck(8), newfs(8), reboot(8)

HISTORY
     The fsirand command appeared in SunOS 3.x.  This version of fsirand first
     appeared in OpenBSD 2.1.

AUTHORS
     Todd C. Miller

CAVEATS
     Since fsirand allocates enough memory to hold all the inodes in a given
     cylinder group, it may use a large amount of memory for large disks with
     few cylinder groups.

OpenBSD 4.7                      May 31, 2007                                1
