mkfs_ufs man page on SmartOS

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MKFS_UFS(1M)							  MKFS_UFS(1M)

       mkfs_ufs - construct a UFS file system

       mkfs -F ufs [generic_options] [-o FSType_specific_options] raw_device_file

       The  UFS-specific  module  of mkfs builds a UFS file system with a root
       directory and a lost+found directory (see fsck(1M)).

       The UFS-specific mkfs is rarely run directly. Use the newfs(1M) command

       raw_device_file indicates the disk partition on which to create the new
       file system. If the  -o	N,  -V,	 or  -m	 options  are  specified,  the
       raw_device_file	is not actually modified. size specifies the number of
       disk sectors in the file system, where a disk  sector  is  usually  512
       bytes.  This  argument  must follow the raw_device_file argument and is
       required (even with -o N), unless the -V	 or  -m	 generic  options  are

       generic_options are supported by the generic mkfs command. See mkfs(1M)
       for a description of these options.

       The following generic options are supported:

	     Print the command line that was used to create the existing  file

	     Print the current mkfs command line.

       The following UFS-specific options are supported:

	     Use one or more of the following values separated by commas (with
	     no intervening spaces) to specify UFS-specific options:

			    The number of alternate sectors  per  cylinder  to
			    reserve for bad block replacement for SCSI devices
			    only. The default is 0.

			    This option is not applicable for disks  with  EFI
			    labels and is ignored.

			    The	 logical  block	 size  of  the	file system in
			    bytes, either 4096 or 8192. The default  is	 8192.
			    The	 sun4u	architecture does not support the 4096
			    block size.

			    Sends to stdout a binary  (machine-readable)  ver‐
			    sion  of the superblock that would be used to cre‐
			    ate a file system with the specified configuration

			    Sends  to  stdout  a human-readable version of the
			    superblock that would be used  to  create  a  file
			    system  with  the  specified configuration parame‐

			    The number of cylinders per cylinder group,	 rang‐
			    ing	 from 16 to 256.  The default is calculated by
			    dividing the number of sectors in the file	system
			    by	the number of sectors in a gigabyte. Then, the
			    result is multiplied by 32. The default  value  is
			    always between 16 and 256.

			    The	 per-cylinder-group  meta  data	 must fit in a
			    space no larger than what is available in one log‐
			    ical  file	system block. If too large a cgsize is
			    requested, it is changed  by  the  minimum	amount

			    The	 smallest  amount  of disk space in bytes that
			    can be allocated to a file.	 fragsize  must	 be  a
			    power of 2 divisor of bsize, where:

			    bsize / fragsize is 1, 2, 4, or 8.

			    This means that if the logical block size is 4096,
			    legal values for fragsize are 512, 1024, 2048, and
			    4096.  When	 the logical block size is 8192, legal
			    values are 1024, 2048, 4096, and 8192. The default
			    value is 1024.

			    For	 file  systems	greater than 1 terabyte or for
			    file systems created with the mtb=y option,	 frag‐
			    size is forced to match block size (bsize).

			    The	 minimum  percentage of free space to maintain
			    in the file system	between	 0%  and  99%,	inclu‐
			    sively.  This  space  is off-limits to users. Once
			    the file system is filled to this threshold,  only
			    the	 superuser  can	 continue  writing to the file

			    The default is ((64 Mbytes/partition size) * 100),
			    rounded  down  to  the nearest integer and limited
			    between 1% and 10%, inclusively.

			    This parameter can be subsequently	changed	 using
			    the tunefs(1M) command.

			    Rotational	delay.	This option is obsolete in the
			    Solaris 10 release. The value is always set to  0,
			    regardless of the input value.

			    The maximum number of logical blocks, belonging to
			    one file, that  are	 allocated  contiguously.  The
			    default is calculated as follows:

			      maxcontig = disk drive maximum transfer size / disk block size

			    If	the  disk drive's maximum transfer size cannot
			    be determined, the default value for maxcontig  is
			    calculated from kernel parameters as follows:

			    If	maxphys	 is less than ufs_maxmaxphys, which is
			    typically 1 Mbyte, then maxcontig is set  to  max‐
			    phys.  Otherwise,  maxcontig is set to ufs_maxmax‐

			    You can set	 maxcontig  to	any  positive  integer

			    The	 actual	 value	will be the lesser of what has
			    been specified and what the hardware supports.

			    You can  subsequently  change  this	 parameter  by
			    using tunefs(1M).

			    Set	 the  parameters  of  the file system to allow
			    eventual growth to over a terabyte in  total  file
			    system  size.  This option sets fragsize to be the
			    same as bsize, and sets nbpi to  1	Mbyte,	unless
			    the	 -i  option is used to make it even larger. If
			    you explicitly set the fragsize or nbpi parameters
			    to	values that are incompatible with this option,
			    the user-supplied value of	fragsize  or  nbpi  is

			    Print out the file system parameters that would be
			    used to create the file  system  without  actually
			    creating the file system.

			    The number of bytes per inode, which specifies the
			    density of inodes in the file system.  The	number
			    is	divided into the total size of the file system
			    to determine the number of inodes to create.

			    This value should  reflect	the  expected  average
			    size  of files 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. The default is 2048.

			    The number of inodes can increase if the file sys‐
			    tem is expanded with the growfs command.

			    The	 number	 of  different rotational positions in
			    which to divide a cylinder group. The  default  is

			    This  option  is not applicable for disks with EFI
			    labels and is ignored.

			    The number of sectors per track on the  disk.  The
			    default is 32.

			    The number of tracks per cylinder on the disk. The
			    default is 16.

			    This option is not applicable for disks  with  EFI
			    labels and is ignored.

			    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. The default is time.

			    This parameter can be  subsequently	 changed  with
			    the tunefs(1M) command.

			    The	 rotational  speed of the disk, in revolutions
			    per second. The default is 60.

			    Note that you specify rps for  mkfs	 and  rpm  for

			    This  option  is not applicable for disks with EFI
			    labels and is ignored.

	     Alternatively, parameters can be entered as a list of space-sepa‐
	     rated  values  (without keywords) whose meaning is positional. In
	     this case, the -o option is omitted and the list follows the size
	     operand. This is the way newfs passes the parameters to mkfs.

       The following operands are supported:

			  The disk partition on which to write.

       fsck(1M),  mkfs(1M),  newfs(1M), tunefs(1M), dir_ufs(4), attributes(5),

       The following error message typically occurs  with  very	 high  density
       disks.  On  such	 disks,	 the  file  system structure cannot encode the
       proper disk layout information. However, such disks have enough onboard
       intelligence  to	 make  up  for any layout deficiencies, so there is no
       actual impact on performance. The warning  that	performance  might  be
       impaired can be safely ignored.

	 Warning: insufficient space in super block for
	 rotational layout tables with nsect sblock.fs_nsect
	 and ntrak sblock.fs_ntrak. (File system performance may be impaired.)

       The  following error message occurs when the disk geometry results in a
       situation where the last truncated cylinder group  cannot  contain  the
       correct number of data blocks. Some disk space is wasted.

	 Warning: inode blocks/cyl group (grp) >= data blocks (num) in last cylinder

       If  there  is  only one cylinder group and if the above condition holds
       true, mkfs fails with the following error:

	 File system creation failed. There is only one cylinder group and that is
	 not even big enough to hold the inodes.

       The following error message occurs when the best calculated file system
       layout  is  unable to include the last few sectors in the last cylinder
       group. This is due to the interaction between how much  space  is  used
       for  various  pieces  of	 meta data and the total blocks available in a
       cylinder group. Modifying nbpi and cpg might reduce this number, but it
       is rarely worth the effort.

	 Warning: num sector(s) in last cylinder group unallocated

       You  can	 use lofiadm to create a file that appears to the mkfs command
       (for example, mkfs_pcfs or mkfs_ufs) as a raw device. You can then  use
       the  mkfs  command  to  create  a file system on that device. See lofi‐
       adm(1M) for examples of creating a UFS and a PC (FAT) file system on  a
       device created by lofiadm.

       Both  the  block and character devices, such as devices in /dev/dsk and
       /dev/rdsk, must be available prior to running the mkfs command.

				  Mar 8, 2006			  MKFS_UFS(1M)

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