newfs(8)						      System Manager's Manual							  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-flags] [newfs-options]
	    [special-device] mount-node

DESCRIPTION

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

       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 information in the disk label.  If the disk has not been labeled using the disklabel 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 system 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 parameters 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 parameters, 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  supporting  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.

FLAGS

       This section describes the file system dependencies for the UFS file systems.

       Displays the file system parameters without creating the file system.

       The following newfs-options flags define the general layout policies.  The block size of the file system in bytes.   Note  that	the  block
       size is fixed at 8KB.  The fragment size of the file system in bytes.  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.   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.  This specifies the maximum number of contigu-
       ous 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.  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.  This indicates the maximum number of blocks any single
       file can allocate 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.	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.  The number of cylinders per cylinder group in a file sys-
       tem.  The default value is 16.  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.  The speed of the disk in revolutions per minute.  The size of a sector
       in bytes (almost never anything but 512).  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).  The number of tracks per cylinder available for data
       allocation by the file system.  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.	Spare sec-
       tors (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 allocation.  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 log-
	      ical sector 1.  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.  The following option applies only to mfs:
	      Used for providing a decimal numeric value to be passed as mount flags when running as a memory based file system.  This	option	is
	      primarily intended for use when mfs is started by the mount(8) command.

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

	      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-device and 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-device	is
	      marked  in  use  for fstype in 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 overlapping partitions will be marked UNUSED.  spe-
	      cial-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 spe-
	      cial-device does not exist or is corrupted.
	      Quitting ....

	      The specified device either does not have a disklabel or the disklabel is corrupted.  Error: special-device or an overlapping parti-
	      tion is open.
	      Quitting ....

	      This message indicates that you tried to create a file system on a partition that is open.   Error:  special-device  is  an  invalid
	      device or cannot be opened.
	      Quitting ....

	      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.
	      Quitting ....

	      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 partition special-device.
	      Quitting ....

	      This message indicates that an unknown error was detected.

       The following examples illustrate some of these messages: 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.  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 exist-
	      ing 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.  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...  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 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.   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.  Shut down and reboot the system to synchronize the in-memory and on-disk
       system configuration data bases.  Create the 512 Mbyte mfs, mounted on /tmp: #/usr/sbin/mfs -s 10000000 /tmp

FILES

       Specifies the command path.  Specifies the command path.  Provides disk geometry and file system partition information.

RELATED INFORMATION

       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) delim off

																	  newfs(8)