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NetBSD 6.1.5 - man page for newfs_ext2fs (netbsd section 8)

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

NAME
     newfs_ext2fs -- construct a new ext2 file system

SYNOPSIS
     newfs_ext2fs [-FINZ] [-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.  Typically the defaults are reasonable, however newfs_ext2fs has numerous
     options to allow the defaults to be selectively overridden.

     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 compatibil-
		 ity with ext4.

     -F 	 Create a file system image in special.  The file system size needs to be speci-
		 fied 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 with block-
		 size because the current ext2fs implementation 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 minimum 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 sys-
			    tems that can be understood by old or dumb firmwares for bootstrap.
			    (default)
		       1    'DYNAMIC_REV'; various extended (and sometimes incompatible) features
			    are enabled (though not all features are supported on NetBSD).  Cur-
			    rently only the following features are supported:
				  RESIZE       Prepare some reserved structures 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.

     -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 arguments, except that the number is converted into sectors by
		 dividing by the sector size (as specified by -S secsize) after suffix interpre-
		 tation.

		 If no -s size is specified then the filesystem size defaults to that of the par-
		 tition, or, if -F is specified, the existing 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 displayed (no progress
			    bar).
		 The default is 3.  If -N is specified newfs_ext2fs stops before 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 image 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 superblock 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 improve 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), diskpart(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,
     http://e2fsprogs.sourceforge.net/ext2intro.html.

HISTORY
     The newfs_ext2fs command first appeared in NetBSD 5.0.

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 inde-
     pendently.

     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 supported 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 NetBSD distribution for resizing ext2 file systems yet.

BSD					  March 1, 2009 				      BSD
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