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newfs(8)							     newfs(8)



NAME

  newfs, mfs - Constructs a new	UFS file system

SYNOPSIS

  /usr/sbin/newfs [-N] [newfs-options] special-device [disk-type]

  /usr/sbin/mfs	[-F mount-options] [newfs-options] [special-device] mount-
  node

OPTIONS

  This section describes the file system dependencies for the UFS file sys-
  tems.

  -N  Displays the file	system parameters without creating the file system.

  The following	newfs-options define the general layout	policies.

  -b block-size
      The block	size of	the file system	in bytes.  Note	that the block size
      is fixed at 8KB.

  -f frag-size
      The fragment size	of the file system in bytes.

  -m %free_space
      The percentage of	space reserved from normal users; the minimum free
      space threshold (minfree).  The default value is 10%. See	tunefs(8) for
      more details on how to set this option.

  -o opt_preference
      The file system can either be instructed to try to minimize the time
      spent allocating blocks, or to try to minimize the space fragmentation
      on the disk.  If the value of minfree is less than 10%, the default is
      to optimize for space; if	the value of minfree is	greater	than or	equal
      to 10%, the default is to	optimize for time. See tunefs(8) for more
      details on how to	set this option.

  -a maxcontig
      This specifies the maximum number	of contiguous blocks that are laid
      out before forcing a rotational delay (refer to the -d option); that
      is, the number of	blocks that can	be combined into a single read
      request (cluster). The default value is 8.  See tunefs(8)	for more
      details on how to	set this option.

  -d rotdelay
      This specifies the expected time (in milliseconds) to service a
      transfer completion interrupt and	initiate a new transfer	on the same
      disk. The	default	is zero	milliseconds.  See tunefs(8) for more details
      on how to	set this option.

  -e maxbpg
      This indicates the maximum number	of blocks any single file can allo-
      cate out of a cylinder group before it is	forced to begin	allocating
      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.

  -i #bytes/inode
      This specifies the density of inodes in the file system. The default is
      to create	an inode for each 4096 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.

  -c #cylinders/group
      The number of cylinders per cylinder group in a file system.  The
      default value is 16.

  -s size
      The size of the file system in sectors.

  The following	options	override the default sizes for the disk	geometry.
  The default values are taken from the	disk label. Changing the defaults is
  useful only if you are using newfs to	build (create) a file system whose
  raw image will eventually be used on a different type	of disk	(on a write-
  once disk, for example). Note	that changing any of these values from their
  defaults makes it impossible for fsck	to find	the alternate superblocks if
  the standard superblock is lost.

  -r revolutions/minute
      The speed	of the disk in revolutions per minute.

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

  -u sectors/track
      The number of sectors per	track available	for data allocation by the
      file system.  This does not include sectors reserved at the end of each
      track for	bad block replacement (see -p).

  -t #tracks/cylinder
      The number of tracks per cylinder	available for data allocation by the
      file system.

  -p spare_sectors/track
      Spare sectors (bad sector	replacements) are physical sectors that
      occupy space at the end of each track. They are not counted as part of
      the sectors per track (-u) since they are	not available to the file
      system for data allocation.

  -x spare_sectors/cylinder
      Spare sectors (bad sector	replacements) are physical sectors that
      occupy space at the end of the last track	in the cylinder. They are
      deducted from the	sectors	per track (-u) of the last track of each
      cylinder since they are not available to the file	system for data	allo-
      cation.

  -l hardware_sector_interleave
      Used to describe perturbations in	the media format to compensate for a
      slow controller. Interleave is physical sector interleave	on each
      track, specified as the denominator of the ratio:	sectors	read/sectors
      passed over.

      Thus, an interleave of 1/1 implies contiguous layout, while 1/2 implies
      logical sector 0 (zero) is separated by one sector from logical sector
      1.

  -k sector0-skew/track
      Used to describe perturbations in	the media format to compensate for a
      slow controller. Track skew is the offset	of sector 0 (zero) on track N
      relative to sector 0 (zero) on track N-1 on the same cylinder.

  -F mount-options
      This option applies only to mfs. It is used for providing	a decimal
      numeric value to be passed as mount options when running as a memory
      based file system.  This option is primarily intended for	use when mfs
      is started by the	mount(8) command.

DESCRIPTION

  The newfs command creates a new UFS file system on the specified special-
  device of type disk-type.

				     Note

       The newfs command cannot	be used	to create Advanced File	System
       (AdvFS) domains.	Instead, use the mkfdmn	command, as described in the
       mkfdmn(8) reference page.

  Use the disklabel command to label disks and the newfs command to create
  UFS file systems on the disks.

  If you have labeled the disk by using	the disklabel command, newfs builds a
  UFS file system on the specified device, basing its defaults on the infor-
  mation in the	disk label.  If	the disk has not been labeled using the	disk-
  label	command, newfs fails, displaying the message  disk not labeled.	 When
  this happens,	use the	disklabel command to install a label.

  The mfs command builds a memory file system (mfs), which is a	UFS file sys-
  tem in virtual memory, and mounts it on the specified	mount-node.  When the
  file system is unmounted, mfs	exits and the contents of the file system are
  lost.	 If mfs	is sent	a signal while running,	for example during system
  shutdown, it attempts	to unmount its corresponding file system.  The param-
  eters	for mfs	are almost the same as those for newfs.	 For a memory file
  system, the special-device file provides only	a set of configuration param-
  eters, including the size of the virtual memory segment to allocate.	If
  the special-device file is omitted, you must specify the segment size.  The
  special-device file is usually the primary swap area,	because	that is	where
  the file system is backed up when free memory	gets low and the memory	sup-
  porting the file system has to be paged.

  You can enable /tmp as a memory file system by adding	an entry in the
  /etc/fstab file. For example,	the following line creates a 10	Megabyte
  memory file system, mounted on /tmp:

	    -s20480	       /tmp   mfs rw 1 0

  Note that the	contents of a memory file system are lost whenever a reboot
  or unmount is	performed.

  You must be superuser	to use both commands.

NOTES

  When using newfs to create a UFS file	system on an LSM volume, follow	these
  guidelines:

    +  The disk-type variable may be specified to enable newfs to obtain disk
       attributes such as number of sectors (ns), number of tracks (nt), and
       number of cylinders (nc)	from the /etc/disktab file. The	newfs command
       may get this information	from /etc/disktab because an LSM volume	has
       no disk label.

    +  When specifying disk-type, you can use any entry	in /etc/disktab	that
       has positive values for the disk	attributes (except rx##	entries).
       Since the entries for disks with	dynamic	geometry (such as RAID,	re,
       SWXCR, and hsz##) have a	value of -1 for	these attributes, such disk
       types cannot be specified to newfs.  Instead, use another entry whose
       characteristics match those of the volume (for example, rz##).  Or,
       you can create a	customized entry in /etc/disktab.

    +  The -s option can be omitted, because newfs queries LSM for the size
       of the LSM volume.

ERRORS

  You may receive the following	messages when using the	newfs command:

    +  newfs: /dev/rvol/diskgroup/volname: only	0 partitions

       This error occurs when you attempt to create a file system on an	LSM
       volume and fail to specify the disk-type	parameter correctly. See the
       NOTES section for details.

    +  Warning:	nn sector(s) in	last cylinder unallocated

       This message is for UFS only.  It requires no user action. The message
       indicates that if nn sectors are	added to the size of the file system,
       it will be an integral number of	cylinders.  Disk space is not wasted.
       Usually,	cylinder boundaries are	ignored	when partitions	are allo-
       cated.

    +  Warning:	inode blocks/cyl group (inumber) >>= data blocks	(dnumber) in
       last cylinder group. This implies snumber sector(s) cannot be allo-
       cated

       This message requires no	user action. It	indicates that inumber of
       file system blocks were needed to allocate the inode table but only
       dnumber of file system blocks were available in the last	cylinder
       group. The last cylinder	group could not	be allocated and snumber of
       sectors are actually wasted.

    +  Warning:	special-deviceand overlapping partition(s) are marked in use.
       If you continue with the	operation you can possibly destroy existing
       data. CONTINUE? [y/n]

       The specified partition overlaps	with another partition or partitions
       that has	the fstype field set.

    +  Warning:	partition(s) which overlap special-device are marked in	use.
       If you continue with the	operation you can possibly destroy existing
       data. CONTINUE? [y/n]

       The specified partition overlaps	with another partition or partitions
       that has	the fstype field set.

    +  Warning:	special-deviceis marked	in use for fstypein the	disklabel.
       The partition you are changing already has a file system	on it. This
       is not an error just a warning.

       The partition you are changing already has a file system	on it.

    +  special-device is marked	in use for fstype in the disklabel.  If	you
       continue	with the operation you can possibly destroy existing data.
       CONTINUE? [y/n]

       This message indicates that you tried to	create a file system on	a
       partition that is not currently in active use but is marked for use in
       the disk	label's	partition map. For example, the	partition may be part
       of an LSM volume	or an AdvFS domain.

       If you know that	the partition you specified to newfs does not contain
       any useful data,	you can	choose to override the warning.	 In this
       case, the fstype	in the disk label will be modified to 4.2BSD.

       Note that you can use the command disklabel -s to set the fstype	in
       the disk	label to unused	for partitions that do not contain any valid
       data. See disklabel(8) for more information.

    +  Partition(s) which overlap special-device are marked in use. If you
       continue	with the operation you can possibly destroy existing data.
       CONTINUE? [y/n]

       This message indicates that the partition you specified is not marked
       for use,	but other, overlapping partitions on the disk are marked for
       use.  If	you override this warning, the fstype in the disk's label
       will be modified. The partition you specified to	newfs will be marked
       as in use by the	UFS file system	and labeled with 4.2BSD.  All over-
       lapping partitions will be marked UNUSED.

    +  special-device or an overlapping	partition is open. Quitting...

       This message indicates that you tried to	create a file system on	a
       partition that is actively in use.

    +  Error: the disklabel for	special-device does not	exist or is cor-
       rupted. Quitting	....

       The specified device either does	not have a disklabel or	the disklabel
       is corrupted.

    +  Error: special-deviceor an overlapping partition	is open. Quitting
       ....

       This message indicates that you tried to	create a file system on	a
       partition that is open.

    +  Error: special-deviceis an invalid device or cannot be opened. Quit-
       ting ....

       The specified device is either an invalid device	or it cannot be
       opened.

    +  Error: the disklabel for	special-device could not be updated. Quitting
       ....

       This message indicates that the disklabel on the	specified device
       could not be updated.

    +  Error:: unable to check special-device against active AdvFS domains
       because the directory /etc/fdmns	seems to be missing or wrong. Quit-
       ting ....

       This message indicates that there was a failure when checking overlap
       with AdvFS domains. Either /etc/fdmns or	/etc/fdmns/dom are not active
       domains or they do not exist.

    +  Error: unable to	check special-device against active swap devices
       because special swap files are missing. Quitting	....

       This message indicates that there was a failure when checking overlap
       with active swap	devices.  The special device files associated with
       active swap devices are invalid.

    +  Error: unknown overlap condition	errno encountered for
       partitionspecial-device.	Quitting ....

       This message indicates that an unknown error was	detected.

  The following	examples illustrate some of these messages:

   1.  Creating	a file system on a partition that is marked for	use:


	    # /usr/sbin/newfs /dev/rdisk/dsk11g

	    /dev/rdisk/dsk11g is marked	in use for LSMpubl in the disklabel.
	    If you continue with the operation you can possibly	destroy
	    existing data.
	    CONTINUE? [y/n]

       Partition g of disk dsk11 is part of a disk marked for use by LSM. If
       LSM is not actively using this partition	and the	partition does not
       contain any useful data,	you may	want to	override this warning, by
       answering y. In this case, partition g will be marked as	4.2BSD in the
       disk label.

   2.  Creating	a file system on a partition whose overlapping partitions are
       marked for use:


	    # /usr/sbin/newfs /dev/rdisk/dsk11c

	    Partition(s) which overlap /dev/rdisk/dsk11c are marked in use.
	    If you continue with the operation you can possibly	destroy
	    existing data.
	    CONTINUE? [y/n]

       If you answer y,	partition c on disk dsk11 will be marked 4.2BSD	in
       the disk	label and all partitions that overlap c	will be	marked
       UNUSED.

   3.  Creating	a file system on a partition that is open:


	    # /usr/sbin/newfs /dev/rdisk/dsk11g

	    /dev/rdisk/dsk11g or an overlapping	partition is open.
	    Quitting...

   4.  Creating	a file system on disk that does	not have a disk	label:


	    # /usr/sbin/newfs /dev/rdisk/dsk11c

	    The	disklabel for /dev/rdisk/dsk11c	does not exist or is corrupted.
	    Quitting...

       See disklabel(8)	for information	on installing a	disk label on a	disk.

EXAMPLES

  The following	examples show how to create an mfs file	system.	Both examples
  assume that the process system attributes are	at the system default values,
  per-proc-data-size is	set at 134217728 bytes and max-per-proc-data-size is
  set at 1073741824 bytes (1 Gbyte).

  The following	example	creates	an mfs of 128 Mbytes, mounted on /tmp:

       # /usr/sbin/mfs -s250000	/tmp

  The following	example	creates	an mfs of 512 Mbytes, which is one half
  Gbyte), mounted on /tmp.  Note that two events must happen before you
  create and mount the mfs file	system.	 First,	the process system attribute
  per-proc-data-size must be increased to a new	maximum	value that is equal
  to or	greater	than the size of the mfs file system you want to create.
  Second, the system must be shut down and rebooted so that the	new per-
  proc-data-size value can be placed in	both the in-memory and the on-disk
  system configuration data bases.

   1.  Modify the /etc/sysconfigtab file to change the entry for the per-
       proc-data-size to the following:


		    per_proc_data_size = 536870912

       See sysconfigdb(8) for information on how to make this change.

   2.  Shut down and reboot the	system to synchronize the in-memory and	on-
       disk system configuration data bases.

   3.  Create the 512 Mbyte mfs, mounted on /tmp:


	    #/usr/sbin/mfs -s 10000000 /tmp



FILES

  /usr/sbin/newfs
      Specifies	the command path.

  /usr/sbin/mfs
      Specifies	the command path.

  /etc/disktab
      Provides disk geometry and file system partition information.

SEE ALSO

  Commands: chmod(1), disklabel(8), fsck(8), mkfdmn(8),	mount(8), tunefs(8)

  Files: disktab(4), fstab(4)

  Functions: check_usage(3), set_usage(3)