Provided by: xfsprogs_2.7.7-1_i386 bug

NAME

       mkfs.xfs - construct an XFS filesystem

SYNOPSIS

       mkfs.xfs [ -b subopt=value ] [ -d subopt[=value] ]
            [ -i subopt=value ] [ -l subopt[=value] ] [ -f ]
            [ -n subopt[=value] ] [ -p protofile ] [ -q ]
            [ -r subopt[=value] ] [ -s subopt[=value] ]
            [ -N ] [ -L label ] device

DESCRIPTION

       mkfs.xfs  constructs  an  XFS  filesystem  by writing on a special file
       using the values found in the arguments of the  command  line.   It  is
       invoked  automatically by mkfs(8) when mkfs is given the -t xfs option.

       In its simplest  (and  most  commonly  used  form),  the  size  of  the
       filesystem  is determined from the disk driver.  As an example, to make
       a filesystem with an internal log on the first partition on  the  first
       SCSI disk, use:

            mkfs.xfs /dev/sda1

       The  metadata  log can be placed on another device to reduce the number
       of disk seeks.  To create a filesystem on the first  partition  on  the
       first  SCSI  disk with a 10000 block log located on the first partition
       on the second SCSI disk, use:

            mkfs.xfs -l logdev=/dev/sdb1,size=10000b /dev/sda1

       Each of the subopt=value elements in the argument  list  above  can  be
       given  as  multiple comma-separated subopt=value suboptions if multiple
       suboptions apply to the same option.  Equivalently,  each  main  option
       can be given multiple times with different suboptions.  For example, -l
       internal,size=10000b and -l internal -l size=10000b are equivalent.

       In the descriptions below, sizes are given in sectors,  bytes,  blocks,
       kilobytes,  megabytes,  or gigabytes.  Sizes are treated as hexadecimal
       if prefixed by 0x or 0X, octal if prefixed by 0, or decimal  otherwise.
       If  suffixed with s then the size is converted by multiplying it by the
       filesystems sector size (defaults to 512, see  -s  option  below).   If
       suffixed  with  b  then  the size is converted by multiplying it by the
       filesystems block size (defaults to  4K,  see  -b  option  below).   If
       suffixed  with  k then the size is converted by multiplying it by 1024.
       If suffixed with m then the size is converted by multiplying it by  one
       megabyte  (1024  *  1024  bytes).   If suffixed with g then the size is
       converted by multiplying it by one gigabyte (1024 * 1024 * 1024 bytes).
       If  suffixed with t then the size is converted by multiplying it by one
       terabyte (1024 * 1024 * 1024 * 1024 bytes).  If suffixed  with  p  then
       the  size is converted by multiplying it by one petabyte (1024 * 1024 *
       1024 * 1024 * 1024 bytes).   If  suffixed  with  e  then  the  size  is
       converted by multiplying it by one exabyte (1024 * 1024 * 1024 * 1024 *
       1024 * 1024 bytes).

       -b     Block size options.

              This  option  specifies  the  fundamental  block  size  of   the
              filesystem.  The valid suboptions are: log=value and size=value;
              only one can be supplied.  The block size is specified either as
              a  base  two  logarithm value with log=, or in bytes with size=.
              The default value is 4096 bytes (4 KiB), the minimum is 512, and
              the  maximum  is  65536  (64  KiB).  XFS on Linux currently only
              supports pagesize or smaller blocks.

       -d     Data section options.

              These options specify the location, size, and  other  parameters
              of  the  data  section  of the filesystem.  The valid suboptions
              are:  agcount=value,  agsize=value,  file[=value],   name=value,
              size=value,  sunit=value,  swidth=value, su=value, sw=value, and
              unwritten[=value].

              The  agcount  suboption  is  used  to  specify  the  number   of
              allocation  groups.   The  data  section  of  the  filesystem is
              divided into allocation groups to  improve  the  performance  of
              XFS.   More allocation groups imply that more parallelism can be
              achieved  when  allocating  blocks  and  inodes.   The   minimum
              allocation  group size is 16 MiB; the maximum size is just under
              1 TiB.  The data section  of  the  filesystem  is  divided  into
              agcount allocation groups (default value is scaled automatically
              based on the underlying device size).  Setting agcount to a very
              large   number   should   be   avoided,  since  this  causes  an
              unreasonable amount of CPU time to be used when  the  filesystem
              is close to full.

              The  agsize  suboption  is an alternative to using agcount.  The
              argument  provided  to  agsize  is  the  desired  size  of   the
              allocation  group  expressed  in bytes (usually using the m or g
              suffixes).  This value must be  a  multiple  of  the  filesystem
              block  size,  and must be at least 16MiB, and no more than 1TiB,
              and may be automatically adjusted to  properly  align  with  the
              stripe geometry.  The agcount suboption and the agsize suboption
              are mutually exclusive.

              The name suboption can be  used  to  specify  the  name  of  the
              special  file  containing the filesystem.  In this case, the log
              section must be specified as internal (with a size, see  the  -l
              option below) and there can be no real-time section.

              The file suboption is used to specify that the file given by the
              name suboption is a regular file.  The suboption value is either
              0  or  1,  with  1  signifying  that  the file is regular.  This
              suboption is used only to make a filesystem image.  If the value
              is omitted then 1 is assumed.

              The  size  suboption  is  used  to  specify the size of the data
              section.  This suboption is required if -d  file[=1]  is  given.
              Otherwise,  it  is  only  needed if the filesystem should occupy
              less space than the size of the special file.

              The sunit suboption is used to specify the  stripe  unit  for  a
              RAID  device or a logical volume.  The suboption value has to be
              specified in 512-byte block units.   Use  the  su  suboption  to
              specify  the  stripe unit size in bytes.  This suboption ensures
              that data allocations will  be  stripe  unit  aligned  when  the
              current  end  of  file  is  being  extended and the file size is
              larger than 512KiB.  Also inode allocations and the internal log
              will be stripe unit aligned.

              The  su  suboption  is  an  alternative  to using sunit.  The su
              suboption is used to specify the stripe unit for a  RAID  device
              or  a  striped  logical  volume.   The suboption value has to be
              specified in bytes, (usually using the m or g  suffixes).   This
              value must be a multiple of the filesystem block size.

              The  swidth  suboption is used to specify the stripe width for a
              RAID device or a striped logical volume.   The  suboption  value
              has  to  be  specified  in  512-byte  block  units.   Use the sw
              suboption to specify the  stripe  width  size  in  bytes.   This
              suboption  is required if -d sunit has been specified and it has
              to be a multiple of the -d sunit suboption.

              The sw suboption is an alternative  to  using  swidth.   The  sw
              suboption  is used to specify the stripe width for a RAID device
              or striped logical volume.  The suboption value is expressed  as
              a  multiplier of the stripe unit, usually the same as the number
              of stripe members in the logical volume configuration,  or  data
              disks in a RAID device.

              When  a  filesystem  is  created  on  a  logical  volume device,
              mkfs.xfs  will  automatically  query  the  logical  volume   for
              appropriate sunit and swidth values.

              The  unwritten  suboption  is  used to specify whether unwritten
              extents are flagged as such, or not.   The  suboption  value  is
              either  0 or 1, with 1 signifying that unwritten extent flagging
              should occur.  If the suboption  is  omitted,  unwritten  extent
              flagging   is   enabled.   If  unwritten  extents  are  flagged,
              filesystem write performance will  be  negatively  affected  for
              preallocated  file  extents, since extra filesystem transactions
              are required to convert extent flags for the range of  the  file
              written.   This  suboption  should be disabled if the filesystem
              needs to be used on  operating  system  versions  which  do  not
              support the flagging capability.

       -f     Force  overwrite  when an existing filesystem is detected on the
              device.  By default, mkfs.xfs will not write to the device if it
              suspects  that  there  is a filesystem or partition table on the
              device already.

       -i     Inode options.

              This option specifies the inode  size  of  the  filesystem,  and
              other  inode  allocation  parameters.   The XFS inode contains a
              fixed-size part and a  variable-size  part.   The  variable-size
              part,  whose  size  is  affected  by  this  option, can contain:
              directory data, for small directories; attribute data, for small
              attribute  sets;  symbolic  link data, for small symbolic links;
              the extent list for the file, for files with a small  number  of
              extents;  and  the  root  of  a  tree describing the location of
              extents for the file, for files with a large number of  extents.

              The  valid  suboptions for specifying inode size are: log=value,
              perblock=value, and size=value; only one can be  supplied.   The
              inode  size  is  specified  either as a base two logarithm value
              with log=, in bytes with size=, or as the number  fitting  in  a
              filesystem  block  with  perblock=.   The  mininum (and default)
              value is 256 bytes.  The maximum value is 2048 (2  KiB)  subject
              to the restriction that the inode size cannot exceed one half of
              the filesystem block size.

              XFS uses 64-bit inode numbers internally; however, the number of
              significant  bits  in  an inode number is affected by filesystem
              geometry.  In practice, filesystem size and inode size  are  the
              predominant  factors.   The  Linux  kernel  (on  32 bit hardware
              platforms) and most applications cannot currently  handle  inode
              numbers greater than 32 significant bits, so if no inode size is
              given on the command line, mkfs.xfs will  attempt  to  choose  a
              size  such  that  inode  numbers will be < 32 bits.  If an inode
              size is specified, or if  a  filesystem  is  sufficently  large,
              mkfs.xfs  will  warn  if  this  will  create  inode numbers > 32
              significant bits.

              The option maxpct=value  specifies  the  maximum  percentage  of
              space  in  the  filesystem that can be allocated to inodes.  The
              default value is  25%.   Setting  the  value  to  0  means  that
              essentially all of the filesystem can become inode blocks.

              The   option   align[=value]  is  used  to  specify  that  inode
              allocation is or is not aligned.  The value is either  0  or  1,
              with  1  signifying  that  inodes are allocated aligned.  If the
              value is omitted, 1 is assumed.  The default is that inodes  are
              aligned.   Aligned  inode access is normally more efficient than
              unaligned access; alignment must be established at the time  the
              filesystem  is created, since inodes are allocated at that time.
              This option can be used to turn off  inode  alignment  when  the
              filesystem  needs to be mountable by a version of IRIX that does
              not have the inode alignment feature (any release of IRIX before
              6.2, and IRIX 6.2 without XFS patches).

              The  option  attr[=value]  is  used  to  specify  the version of
              extended attribute inline allocation  policy  to  be  used.   By
              default,  this  is  zero.  Once extended attributes are used for
              the first time, the version will be set to either  one  or  two.
              The  current  version  (two) uses a more efficient algorithm for
              managing the available inline inode space than version one does,
              however,  for backward compatibility reasons (and in the absence
              of the attr=2 mkfs option, or the attr2 mount  option),  version
              one  will  be selected by default when attributes are first used
              on a filesystem.

       -l     Log section options.

              These options specify the location, size, and  other  parameters
              of the log section of the filesystem.  The valid suboptions are:
              internal[=value],  logdev=device,   size=value,   version=[1|2],
              sunit=value, and su=value.

              The  internal  suboption is used to specify that the log section
              is a piece of the data section instead of being  another  device
              or logical volume.  The suboption value is either 0 or 1, with 1
              signifying that the log is internal.  If the value is omitted, 1
              is assumed.

              The  logdev  suboption  is  used to specify that the log section
              should reside on a device separate from the data  section.   The
              suboption  value  is the name of a block device.  The internal=1
              and logdev options are mutually exclusive.

              The size suboption is used  to  specify  the  size  of  the  log
              section.

              If  the  log is contained within the data section and size isn’t
              specified, mkfs.xfs will try  to  select  a  suitable  log  size
              depending  on  the  size  of the filesystem.  The actual logsize
              depends on the filesystem block size  and  the  directory  block
              size.

              Otherwise,  the size suboption is only needed if the log section
              of the filesystem should occupy less space than the size of  the
              special  file.  The size is specified in bytes or blocks, with a
              b suffix meaning multiplication by the filesystem block size, as
              described  above.   The overriding minimum value for size is 512
              blocks.  With some combinations of filesystem block size,  inode
              size,  and  directory block size, the minimum log size is larger
              than 512 blocks.

              Using the version suboption to specify a version 2  log  enables
              the  sunit  suboption,  and  allows the logbsize to be increased
              beyond 32K.  Version 2 logs are automatically selected if a  log
              stripe unit is specified.  See sunit and su suboptions, below.

              The  sunit  suboption specifies the alignment to be used for log
              writes.  The suboption value has to  be  specified  in  512-byte
              block  units.   Use  the  su suboption to specify the log stripe
              unit size  in  bytes.   Log  writes  will  be  aligned  on  this
              boundary,  and  rounded  up  to this boundary.  This gives major
              improvements in  performance  on  some  configurations  such  as
              software  raid5  when  the  sunit is specified as the filesystem
              block size.  The equivalent byte value must be a multiple of the
              filesystem   block  size.   Version  2  logs  are  automatically
              selected if the log su suboption is specified.

              The su suboption is an  alternative  to  using  sunit.   The  su
              suboption  is  used  to  specify  the log stripe.  The suboption
              value has to be specified in bytes, (usually using the  s  or  b
              suffixes).   This  value  must  be  a multiple of the filesystem
              block size.  Version 2 logs are automatically  selected  if  the
              log su suboption is specified.

       -n     Naming options.

              These  options  specify  the version and size parameters for the
              naming (directory) area of the filesystem.  The valid suboptions
              are:  log=value,  size=value,  and  version=value.   The  naming
              (directory) version is 1 or 2, defaulting to 2  if  unspecified.
              With  version 2 directories, the directory block size can be any
              power of 2 size from the filesystem block size up to 65536.  The
              block  size  is  specified  either as a base two logarithm value
              with log=, or in bytes with size=.  The default size  value  for
              version  2  directories  is  4096  bytes  (4  KiB),  unless  the
              filesystem block size is larger than 4096,  in  which  case  the
              default  value  is  the  filesystem  block  size.  For version 1
              directories the block size is the same as the  filesystem  block
              size.

       -p protofile
              If  the  optional  -p protofile argument is given, mkfs.xfs uses
              protofile as a prototype file and takes its directions from that
              file.   The  blocks  and  inodes specifiers in the protofile are
              provided for backwards compatibility, but are otherwise  unused.
              The  syntax  of  the  protofile is defined by a number of tokens
              separated by spaces or newlines. Note that the line numbers  are
              not  part  of  the  syntax  but  are  meant  to  help you in the
              following discussion of the file contents.

                   1       /stand/diskboot
                   2       4872 110
                   3       d--777 3 1
                   4       usr     d--777 3 1
                   5       sh      ---755 3 1 /bin/sh
                   6       ken     d--755 6 1
                   7               $
                   8       b0      b--644 3 1 0 0
                   9       c0      c--644 3 1 0 0
                   10      fifo    p--644 3 1
                   11      slink   l--644 3 1 /a/symbolic/link
                   12      :  This is a comment line
                   13      $
                   14      $

              Line 1 is a dummy string.  (It was formerly  the  bootfilename.)
              It  is  present  for backward compatibility; boot blocks are not
              used on SGI systems.

              Note that some string of characters must be present as the first
              line  of  the proto file to cause it to be parsed correctly; the
              value of this string is immaterial since it is ignored.

              Line 2 contains two numeric  values  (formerly  the  numbers  of
              blocks   and  inodes).   These  are  also  merely  for  backward
              compatibility: two numeric values must appear at this point  for
              the  proto  file  to  be  correctly parsed, but their values are
              immaterial since they are ignored.

              The lines 3 through 11 specify the  files  and  directories  you
              want  to  include  in  this  filesystem. Line 3 defines the root
              directory. Other directories and files  that  you  want  in  the
              filesystem  are  indicated  by  lines  4  through  6 and lines 8
              through 10. Line 11 contains symbolic link syntax.

              Notice the dollar sign ( $ )  syntax  on  line  7.  This  syntax
              directs  the  mkfs.xfs  command  to  terminate the branch of the
              filesystem it  is  currently  on  and  then  continue  from  the
              directory specified by the next line,in this case line 8 It must
              be the  last  character  on  a  line.   The  colon  on  line  12
              introduces  a  comment;  all  characters  up until the following
              newline are ignored.  Note that this means  you  cannot  have  a
              file  in a prototype file whose name contains a colon.  The $ on
              lines  13  and  14  end  the  process,   since   no   additional
              specifications follow.

              File specifications provide the following:

                * file mode
                * user ID
                * group ID
                * the file’s beginning contents

              A  6-character  string  defines  the  mode for a file. The first
              character of this string defines the file  type.  The  character
              range  for  this  first  character  is  -bcdpl.  A file may be a
              regular file, a block special file, a  character  special  file,
              directory  files,  named  pipes (first-in, first out files), and
              symbolic links.  The second character of the mode string is used
              to  specify setuserID mode, in which case it is u.  If setuserID
              mode is not specified, the second character  is  -.   The  third
              character  of  the mode string is used to specify the setgroupID
              mode, in which  case  it  is  g.   If  setgroupID  mode  is  not
              specified,  the second character is -.  The remaining characters
              of the mode string are a three digit octal  number.  This  octal
              number  defines  the  owner,  group,  and other read, write, and
              execute permissions  for  the  file,  respectively.   Form  more
              information on file permissions, see the chmod(1) command.

              Following  the  mode  character  string  are  two decimal number
              tokens that specify the user and group IDs of the file’s  owner.

              In  a  regular  file, the next token specifies the pathname from
              which the contents and size of the file are copied.  In a  block
              or  character  special  file,  the  next  token  are two decimal
              numbers that specify the major and minor device numbers.  When a
              file  is  a symbolic link, the next token specifies the contents
              of the link.

              When the file is a directory, the mkfs.xfs command  creates  the
              entries  dot  (.)  and  dot-dot  (..) and then reads the list of
              names and file specifications in a recursive manner for  all  of
              the  entries in the directory. A scan of the protofile is always
              terminated with the dollar ( $ ) token.

       -q     Quiet option.

              Normally mkfs.xfs prints the parameters of the filesystem to  be
              constructed; the -q flag suppresses this.

       -r     Real-time section options.

              These  options  specify the location, size, and other parameters
              of  the  real-time  section  of  the  filesystem.    The   valid
              suboptions are: rtdev=device, extsize=value, and size=value.

              The  rtdev  suboption is used to specify the device which should
              contain the real-time section of the filesystem.  The  suboption
              value is the name of a block device.

              The  extsize suboption is used to specify the size of the blocks
              in the real-time section of the filesystem.  This size must be a
              multiple  of  the  filesystem  block  size.  The minimum allowed
              value is the filesystem  block  size  or  4  KiB  (whichever  is
              larger);  the  default  value  is  the  stripe width for striped
              volumes or 64 KiB for non-striped volumes; the  maximum  allowed
              value  is  1 GiB.  The real-time extent size should be carefully
              chosen to match the parameters of the physical media used.

              The size suboption is used to specify the size of the  real-time
              section.  This suboption is only needed if the real-time section
              of the filesystem should occupy less space than the size of  the
              partition or logical volume containing the section.

       -s     Sector size options.

              This  option  specifies  the  fundamental  sector  size  of  the
              filesystem.  The valid suboptions are: log=value and size=value;
              only  one  can be supplied.  The sector size is specified either
              as a base two logarithm value with log=, or in bytes with size=.
              The  default  value  is 512 bytes.  The minimum value for sector
              size is 512; the maximum is 32768 (32  KiB).   The  sector  size
              must  be  a  power  of 2 size and cannot be made larger than the
              filesystem block size.

       -L label
              Set the filesystem label.  XFS filesystem labels can be at  most
              12  characters  long;  if  label  is  longer than 12 characters,
              mkfs.xfs will not proceed with creating the  filesystem.   Refer
              to  the  mount(8) and xfs_admin(8) manual entries for additional
              information.

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

SEE ALSO

       xfs(5), mkfs(8), mount(8), xfs_info(8), xfs_admin(8).

BUGS

       With a prototype file, it is not possible to specify hard links.

                                                                   mkfs.xfs(8)