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NEWFS(8)		FreeBSD	System Manager's Manual		      NEWFS(8)

     newfs -- construct	a new UFS1/UFS2	file system

     newfs [-EJNUjlnt] [-L volname] [-O	filesystem-type] [-S sector-size]
	   [-T disktype] [-a maxcontig]	[-b block-size]
	   [-c blocks-per-cylinder-group] [-d max-extent-size] [-e maxbpg]
	   [-f frag-size] [-g avgfilesize] [-h avgfpdir] [-i bytes]
	   [-k held-for-metadata-blocks] [-m free-space] [-o optimization]
	   [-p partition] [-r reserved]	[-s size] special

     The newfs utility is used to initialize and clear file systems before
     first use.	 The newfs utility builds a file system	on the specified spe-
     cial file.	 (We often refer to the	``special file'' as the	``disk'',
     although the special file need not	be a physical disk.  In	fact, it need
     not even be special.)  Typically the defaults are reasonable, however
     newfs has numerous	options	to allow the defaults to be selectively	over-

     The following options define the general layout policies:

     -E	     Erase the content of the disk before making the filesystem.  The
	     reserved area in front of the superblock (for bootcode) will not
	     be	erased.

	     This option is only relevant for flash based storage devices that
	     use wear-leveling algorithms.

	     Erasing may take a	long time as it	writes to every	sector on the

     -J	     Enable journaling on the new file system via gjournal.  See
	     gjournal(8) for details.

     -L	volname
	     Add a volume label	to the new file	system.

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

     -O	filesystem-type
	     Use 1 to specify that a UFS1 format file system be	built; use 2
	     to	specify	that a UFS2 format file	system be built.  The default
	     format is UFS2.

     -T	disktype
	     For backward compatibility.

     -U	     Enable soft updates on the	new file system.

     -a	maxcontig
	     Specify the maximum number	of contiguous blocks that will be laid
	     out before	forcing	a rotational delay.  The default value is 16.
	     See tunefs(8) for more details on how to set this option.

     -b	block-size
	     The block size of the file	system,	in bytes.  It must be a	power
	     of	2.  The	default	size is	32768 bytes, and the smallest allow-
	     able size is 4096 bytes.  The optimal block:fragment ratio	is
	     8:1.  Other ratios	are possible, but are not recommended, and may
	     produce poor results.

     -c	blocks-per-cylinder-group
	     The number	of blocks per cylinder group in	a file system.	The
	     default is	to compute the maximum allowed by the other parame-
	     ters.  This value is dependent on a number	of other parameters,
	     in	particular the block size and the number of bytes per inode.

     -d	max-extent-size
	     The file system may choose	to store large files using extents.
	     This parameter specifies the largest extent size that may be
	     used.  The	default	value is the file system blocksize.  It	is
	     presently limited to a maximum value of 16	times the file system
	     blocksize and a minimum value of the file system blocksize.

     -e	maxbpg
	     Indicate the maximum number of blocks any single file can allo-
	     cate out of a cylinder group before it is forced to begin allo-
	     cating blocks from	another	cylinder group.	 The default is	about
	     one quarter of the	total blocks in	a cylinder group.  See
	     tunefs(8) for more	details	on how to set this option.

     -f	frag-size
	     The fragment size of the file system in bytes.  It	must be	a
	     power of two ranging in value between blocksize/8 and blocksize.
	     The default is 4096 bytes.

     -g	avgfilesize
	     The expected average file size for	the file system.

     -h	avgfpdir
	     The expected average number of files per directory	on the file

     -i	bytes
	     Specify the density of inodes in the file system.	The default is
	     to	create an inode	for every (2 * frag-size) bytes	of data	space.
	     If	fewer inodes are desired, a larger number should be used; to
	     create more inodes	a smaller number should	be given.  One inode
	     is	required for each distinct file, so this value effectively
	     specifies the average file	size on	the file system.

     -j	     Enable soft updates journaling on the new file system.  This flag
	     is	implemented by running the tunefs(8) utility found in the
	     user's $PATH.

     -k	held-for-metadata-blocks
	     Set the amount of space to	be held	for metadata blocks in each
	     cylinder group.  When set,	the file system	preference routines
	     will try to save the specified amount of space immediately	fol-
	     lowing the	inode blocks in	each cylinder group for	use by meta-
	     data blocks.  Clustering the metadata blocks speeds up random
	     file access and decreases the running time	of fsck(8).  By
	     default newfs sets	it to half of the space	reserved to minfree.

     -l	     Enable multilabel MAC on the new file system.

     -m	free-space
	     The percentage of space reserved from normal users; the minimum
	     free space	threshold.  The	default	value used is defined by
	     MINFREE from <ufs/ffs/fs.h>, currently 8%.	 See tunefs(8) for
	     more details on how to set	this option.

     -n	     Do	not create a .snap directory on	the new	file system.  The
	     resulting file system will	not support snapshot generation, so
	     dump(8) in	live mode and background fsck(8) will not function
	     properly.	The traditional	fsck(8)	and offline dump(8) will work
	     on	the file system.  This option is intended primarily for	memory
	     or	vnode-backed file systems that do not require dump(8) or
	     fsck(8) support.

     -o	optimization
	     (space or time).  The file	system can either be instructed	to try
	     to	minimize the time spent	allocating blocks, or to try to	mini-
	     mize the space fragmentation on the disk.	If the value of	min-
	     free (see above) is less than 8%, the default is to optimize for
	     space; if the value of minfree is greater than or equal to	8%,
	     the default is to optimize	for time.  See tunefs(8) for more
	     details on	how to set this	option.

     -p	partition
	     The partition name	(a..h) you want	to use in case the underlying
	     image is a	file, so you do	not have access	to individual parti-
	     tions through the filesystem.  Can	also be	used with a device,
	     e.g., newfs -p f /dev/da1s3 is equivalent to newfs	/dev/da1s3f.

     -r	reserved
	     The size, in sectors, of reserved space at	the end	of the parti-
	     tion specified in special.	 This space will not be	occupied by
	     the file system; it can be	used by	other consumers	such as
	     geom(4).  Defaults	to 0.

     -s	size
	     The size of the file system in sectors.  This value defaults to
	     the size of the raw partition specified in	special	less the
	     reserved space at its end (see -r).  A size of 0 can also be used
	     to	choose the default value.  A valid size	value cannot be	larger
	     than the default one, which means that the	file system cannot
	     extend into the reserved space.

     -t	     Turn on the TRIM enable flag.  If enabled,	and if the underlying
	     device supports the BIO_DELETE command, the file system will send
	     a delete request to the underlying	device for each	freed block.
	     The trim enable flag is typically set when	the underlying device
	     uses flash-memory as the device can use the delete	command	to
	     pre-zero or at least avoid	copying	blocks that have been deleted.

     The following options override the	standard sizes for the disk geometry.
     Their default values are taken from the disk label.  Changing these
     defaults is useful	only when using	newfs 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 any of these	values from their defaults will	make it	impos-
     sible for fsck(8) to find the alternate superblocks if the	standard
     superblock	is lost.

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

	   newfs /dev/ada3s1a

     Creates a new ufs file system on ada3s1a.	The newfs utility will use a
     block size	of 32768 bytes,	a fragment size	of 4096	bytes and the largest
     possible number of	blocks per cylinders group.  These values tend to pro-
     duce better performance for most applications than	the historical
     defaults (8192 byte block size and	1024 byte fragment size).  This	large
     fragment size may lead to much wasted space on file systems that contain
     many small	files.

     fdformat(1), geom(4), disktab(5), fs(5), camcontrol(8), dump(8),
     dumpfs(8),	fsck(8), gpart(8), gjournal(8),	growfs(8), gvinum(8),
     makefs(8),	mount(8), tunefs(8)

     M.	McKusick, W. Joy, S. Leffler, and R. Fabry, "A Fast File System	for
     UNIX", ACM	Transactions on	Computer Systems 2, 3, pp 181-197, August
     1984, (reprinted in the BSD System	Manager's Manual).

     The newfs utility appeared	in 4.2BSD.

FreeBSD	11.0			 July 15, 2015			  FreeBSD 11.0


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