mkfs - construct a VxFS file system
/usr/sbin/mkfs [-F vxfs] [-V] -m special
/usr/sbin/mkfs [-F vxfs] [-V]
[-o [N] [X] [ninode=n] [nau=n] [bsize=n] [logsize=n] [ausize=n]
[aufirst=n] [aupad=n] [version=n] [inosize=n]
[largefiles|nolargefiles] ] special size
mkfs creates a VxFS file system by writing on the special device file,
unless either the -o N or -m option is specified. special must be the
first argument after the options are given. The file system is
created based on the options and size specified on the command line.
The numeric size specifies the number of sectors in the file system.
By default, size is specified in units of DEV_BSIZE sectors
(currently, 1024 bytes). If size is not specified, mkfs determines
the size of the special device.
size can also be specified with a suffix to indicate a unit of measure
other than sectors. Append k or K to indicate the value is in
kilobytes, m or M to indicate megabytes, or g or G to indicate
gigabytes. An appended letter can be separated from the number by a
space. In that case, enclose the letter and number in a set of
quotes, for example:
mkfs builds a file system with a root directory and a lost+found
directory (see fsck_vxfs(1M)). The file system can have disk layout
Version 2, disk layout Version 3, or disk layout Version 4. Version 2
supports dynamic inode allocation. Version 3 adds support for large
files and large UIDs. Version 4 adds support for Access Control
Lists. On HP-UX 11.1x systems, the default is Version 4. On HP-UX
11.0 systems, the default is Version 3. You can choose the disk
layout version with the version=n option (see below).
Inode allocation is done dynamically. There are a minimum number of
inodes allocated to the file system by mkfs, and any other inode
allocations are done on an as-needed basis during file system use.
mkfs recognizes the following options:
-F vxfs Specify the VxFS file system type.
-m Display the command line which was used to create
the file system. The file system must already
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-V Echo the completed command line, but do not
execute the command. The command line is
generated by incorporating the user-specified
options and other information derived from
/etc/fstab. This option allows the user to verify
the command line.
Specify options specific to the VxFS file system
type. specific_options is a comma separated list
of suboptions and/or keyword/attribute pairs.
The following specific_options are valid on a VxFS
N Do not write the file system to the special
file. This option gives all the information
needed to create a file system but does not
X Create a file system in a file. Used for
n is the starting block number, in blocks of
size bsize, of the first allocation unit.
This option allows the allocation units to be
aligned to a particular boundary, such as a
cylinder boundary. This option is not
applicable to Version 3 and 4 disk layouts,
which always set the starting block number to
n is the size, in blocks of size bsize, of
the padding to leave between the end of the
inode list and the first data block in each
allocation unit. This option allows the data
blocks of an allocation unit to be aligned to
a particular boundary, such as a cylinder
boundary. This option is ignored for Version
3 and 4 disk layouts.
n is the size, in blocks of size bsize, of an
allocation unit. This option is not
applicable to the Version 3 and 4 disk
layouts, which fix the allocation unit size
at 32768. For disk layout Version 2, this is
an alternate way of specifying the number of
allocation units. This option cannot be used
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with the nau option. With ausize, the last
allocation unit on the file system can be
shorter than the others. If the last
allocation unit on the file system is not
long enough to contain an entire allocation
unit header, the size of the resulting file
system is shortened to the end of the last
complete allocation unit. This parameter may
not exceed 262144 blocks.
The algorithm used to choose the default
value is rather complicated, but is intended
to balance the number of allocation units (4
to 16 is a good range), the size of the
allocation units (at least 32768 blocks), and
n is the block size for files on the file
system and represents the smallest amount of
disk space allocated to a file. n must be a
power of 2 selected from the range 1024 to
8192. The default is 1024 for file systems
less than 8 gigabytes, 2048 for file systems
less than 16 gigabytes, 4096 for file systems
less than 32 gigabytes, and 8192 for larger
n is the on-disk inode structure size for
files on the file system. The valid values
are 256 and 512 bytes. The default is 256.
There is usually no reason to increase the
inode size, and not using the default value
can adversely affect file system performance.
Valid only for the Version 3 and 4 disk
layouts. Controls the largefiles flag for
the file system. If largefiles is specified,
the bit is set and files two gigabytes or
larger can be created. If nolargefiles is
specified, the bit is cleared and files
created on the file system are limited to
less than two gigabytes. The default is
nolargefiles. See fsadm_vxfs(1M).
NOTE: Large files are supported on HP-UX
10.20 systems and above. Be careful when
implementing large file system capability.
System administration utilities such as
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backup may not operate correctly if they are
not large-file aware.
n is the number of file system blocks to
allocate for an activity logging area. The
minimum value for Version 2 and 3 disk
layouts is 32 blocks. The minimum value for
Version 4 disk layouts is the number of
blocks that make the log no less than 256K.
The maximum value for n is the number of
blocks that make the log no greater than
16384K. This means that for a bsize of 1024,
2048, 4096, or 8192 bytes the maximum value
of logsize is 16384, 8192, 4096, or 2048
blocks, respectively. To avoid wasting
space, the default logsize is 1024 blocks for
a file system 8 megabytes or larger, 128
blocks for a file system 2 megabytes or
larger but less than 8 megabytes, and 32
blocks for a file system less than 2
A large log provides better performance on
metadata-intensive workloads. A small log
uses less space on the disk and leaves more
room for file data. for example, and NFS-
intensive workload performs better with a
large log; a small floppy device requires a
NOTE: The amount of virtual memory required
by fsck (see fsck_vxfs(1M)) to check a VxFS
file system is proportional to the size of
the log. The maximum amount of virtual
memory used is twice the size of the log.
Therefore, the sum of physical memory and
swap space must be at least 32 MB to ensure
that a file system with a 16384K log can be
cleaned. On small systems, take care not to
create a file system with a log larger than
half the available swap space. A maximum log
size of one third the total of memory and
swap space is a good rule of thumb (see
n is the number of allocation units on the
file system. This option is not applicable
to the Version 3 and 4 disk layouts. For
disk layout Version 2, if nau is specified,
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then ausize is determined by evenly dividing
the sectors among the allocation units. By
default, the number of allocation units is
based on the value of ausize.
n is the maximum number of inodes in the file
system. The actual maximum number of inodes
is n rounded up to an appropriate boundary.
The digit 0 and the string unlimited both
mean that the number of inodes is unlimited.
The default is unlimited.
n is the VxFS disk layout version number.
Valid values are 2, 3, and 4.
To use mkfs to create a VxFS file system on /dev/rdsk/c0t6d0:
mkfs -F vxfs /dev/rdsk/c0t6d0 1024
To use mkfs to determine the command that was used to create the VxFS
file system on /dev/rdsk/c0t6d0:
mkfs -F vxfs -m /dev/rdsk/c0t6d0
To create a VxFS file system on /dev/vgqa/lvol1, with a Version 4 disk
layout and largefiles capability:
mkfs -F vxfs -o version=4,largefiles /dev/vgqa/lvol1
If you want to reuse a special device that was previously used by LVM,
you must first wipe out all the LVM information remaining on the disk.
Use pvremove(1M) to remove the LVM information before executing
mkfs_vxfs(1M). (You can also remove the LVM information by
initializing the device with mediainit(1), but that is slower.)
The -o largefiles option should be used with care, since older
applications will not react correctly when confronted with large
Upon successful completion, the mkfs command returns a value of 0.
The return value is 1 if a syntax error occurs. Other errors return a
value of 32.
bdf(1M), chmod(1), chown(2), df_vxfs(1M), fs_vxfs(4), fsadm_vxfs(1M),
fsck_vxfs(1M), group(4), mkfs(1M), mount_vxfs(1M), newfs_vxfs(1M),
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mkfs : SVID3
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