NEWFS_EXT2FS(8)         OpenBSD System Manager's Manual        NEWFS_EXT2FS(8)

NAME
     newfs_ext2fs - construct a new ext2 file system

SYNOPSIS
     newfs_ext2fs [-FINqZ] [-b block-size] [-D inodesize] [-f frag-size]
                  [-i bytes-per-inode] [-m free-space] [-n inodes]
                  [-O filesystem-format] [-S sector-size] [-s size]
                  [-V verbose] [-v volname] special

DESCRIPTION
     newfs_ext2fs is used to initialize and clear ext2 file systems before
     first use.  Before running newfs_ext2fs the disk must be labeled using
     disklabel(8).  newfs_ext2fs builds a file system on the specified special
     device, basing its defaults on the information in the disk label.  Typi-
     cally the defaults are reasonable, although newfs_ext2fs has numerous op-
     tions to allow the defaults to be selectively overridden.

     The special file should be a raw device, for example /dev/rsd0a; if a
     relative path like sd0a is specified, the corresponding raw device is
     used.

     Options with numeric arguments may contain an optional (case-insensitive)
     suffix:

           b    Bytes; causes no modification.  (Default)
           k    Kilo; multiply the argument by 1024.
           m    Mega; multiply the argument by 1048576.
           g    Giga; multiply the argument by 1073741824.

     The following options define the general layout policies.

     -b block-size
                 The block size of the file system, in bytes.  It must be a
                 power of two.  The smallest allowable size is 1024 bytes.
                 The default size depends upon the size of the file system:

                       file system size  block-size
                       <= 512 MB         1 KB
                       > 512 MB          4 KB

     -D inodesize
                 Set the inode size.  Defaults to 128, and can also be set to
                 256 for compatibility with ext4.

     -F          Create a file system image in special.  The file system size
                 needs to be specified with ``-s size''.  No attempts to use
                 or update the disk label will be made.

     -f frag-size
                 The fragment size of the file system in bytes.  It must be
                 the same as the blocksize, because the current ext2fs imple-
                 mentation doesn't support fragmentation.

     -I          Do not require that the file system type listed in the disk
                 label is `Linux Ext2'.

     -i bytes-per-inode
                 This specifies the density of inodes in the file system.  If
                 fewer inodes are desired, a larger number should be used; to
                 create more inodes a smaller number should be given.

     -m free-space
                 The percentage of space reserved from normal users; the mini-
                 mum free space threshold.  The default value used is 5%.

     -N          Causes the file system parameters to be printed out without
                 really creating the file system.

     -n inodes   This specifies the number of inodes for the file system.  If
                 both -i and -n are specified then -n takes precedence.  The
                 default number of inodes is calculated from a number of
                 blocks in the file system.

     -O filesystem-format
                 Select the filesystem-format.

                       0    `GOOD_OLD_REV'; this option is primarily used to
                            build root file systems that can be understood by
                            old or dumb firmwares for bootstrap.  (default)
                       1    `DYNAMIC_REV'; various extended (and sometimes in-
                            compatible) features are enabled (though not all
                            features are supported on OpenBSD).  Currently on-
                            ly the following features are supported:

                                  RESIZE       Prepare some reserved struc-
                                               tures which enable future file
                                               system resizing.
                                  FTYPE        Store file types in directory
                                               entries to improve performance.
                                  SPARSESUPER  Prepare superblock backups for
                                               the fsck_ext2fs(8) utility on
                                               not all but sparse block
                                               groups.
                                  LARGEFILE    Enable files larger than 2G
                                               bytes.

     -q          Operate in quiet mode.  Equivalent to -V 1.

     -s size     The size of the file system in sectors.  An `s' suffix will
                 be interpreted as the number of sectors (the default).  All
                 other suffixes are interpreted as per other numeric argu-
                 ments, except that the number is converted into sectors by
                 dividing by the sector size (as specified by -S secsize) af-
                 ter suffix interpretation.

                 If no -s size is specified then the filesystem size defaults
                 to that of the partition, or, if -F is specified, the exist-
                 ing file.

                 If size is negative the specified size is subtracted from the
                 default size (reserving space at the end of the partition).

     -V verbose  This controls the amount of information written to stdout:

                       0    No output.
                       1    Overall size and cylinder group details.
                       2    A progress bar (dots ending at right hand margin).
                       3    The first few super-block backup sector numbers
                            are displayed before the progress bar.
                       4    All the super-block backup sector numbers are dis-
                            played (no progress bar).

                 The default is 4.  If -N is specified newfs_ext2fs stops be-
                 fore outputting the progress bar.

     -v volname  This specifies a volume name for the file system.

     -Z          Pre-zeros the file system image created with -F.  This is
                 necessary if the image is to be used by vnd(4) (which doesn't
                 support file systems with `holes').

     The following option overrides the standard sizes for the disk geometry.
     The default value is taken from the disk label.  Changing this default is
     useful only when using newfs_ext2fs to build a file system whose raw im-
     age will eventually be used on a different type of disk than the one on
     which it is initially created (for example on a write-once disk).  Note
     that changing this value from its default will make it impossible for
     fsck_ext2fs(8) to find the alternative superblocks if the standard su-
     perblock is lost.

     -S sector-size
                 The size of a sector in bytes (almost never anything but
                 512).  Defaults to 512.

NOTES
     There is no option to specify the metadata byte order on the file system
     to be created because the native ext2 file system is always little endian
     even on big endian hosts.

     The file system is created with `random' inode generation numbers to im-
     prove NFS security.

     The owner and group IDs of the root node and reserved blocks of the new
     file system are set to the effective UID and GID of the user initializing
     the file system.

     For the newfs_ext2fs command to succeed, the disk label should first be
     updated such that the fstype field for the partition is set to `Linux
     Ext2', unless -F or -I is used.

     The partition size is found using fstat(2), not by inspecting the disk
     label.  The block size and fragment size will be written back to the disk
     label only if the last character of special references the same partition
     as the minor device number.

SEE ALSO
     fstat(2), disklabel(5), disktab(5), fs(5), disklabel(8), fsck_ext2fs(8),
     mount(8), mount_ext2fs(8), newfs(8)

     Remy Card, Theodore Ts'o, and Stephen Tweedie, "Design and Implementation
     of the Second Extended Filesystem", The Proceedings of the First Dutch
     International Symposium on Linux.

HISTORY
     The newfs_ext2fs command first appeared in OpenBSD 4.7.

AUTHORS
     The newfs_ext2fs command was written by Izumi Tsutsui
     <tsutsui@NetBSD.org>.

BUGS
     The newfs_ext2fs command is still experimental and there are few sanity
     checks.

     The newfs_ext2fs command doesn't have options to specify each REV1 file
     system feature independently.

     The newfs_ext2fs command doesn't support the bad block list accounted by
     the bad blocks inode.

     Many newer ext2 file system features (especially journaling) are not sup-
     ported yet.

     Some features in file systems created by the newfs_ext2fs command might
     not be recognized properly by the fsck_ext2fs(8) utility.

     There is no native tool in the OpenBSD distribution for resizing ext2
     file systems yet.

OpenBSD 4.7                     March 14, 2010                               4
