mkfs_vxfs(1M) mkfs_vxfs(1M)
NAME [Toc] [Back]
mkfs_vxfs: mkfs - construct a VxFS file system
SYNOPSIS [Toc] [Back]
mkfs [-F vxfs] [-V] -m special
mkfs [-F vxfs] [-V] [-o [N] [X] [bsize=bsize] [inosize=n]
[largefiles|nolargefiles] [logsize=n] [ninode=n] [version=n] ]
special size
DESCRIPTION [Toc] [Back]
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 on the command line 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.
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 4 or 5. Version 4 layout adds support for Access Control
Lists. You can choose the disk layout version with the version=n
option (see below).
The number of inodes allocated to a system depends on the disk layout
version. 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.
Options [Toc] [Back]
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 exist.
-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.
-o specific_options
Specify options specific to the VxFS file system type.
specific_options is a comma separated list of
suboptions and/or keyword/attribute pairs.
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The arguments aufirst, aupad, ausize, and nau, are no
longer supported.
The following specific_options are valid on a VxFS file
system:
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 create it.
X Create a file system in a file. Used for
debugging only.
bsize=bsize
bsize is the block size for files on the file
system and represents the smallest amount of disk
space allocated to a file. The value of bsize
must be based on a power of 2 selected from the
range 1024 bytes to 8192 bytes. The default is
1024 bytes for file systems smaller than two
terabytes. For Version 5 disk layout file systems
larger than two terabytes, the maximum file system
size is dependent on the block size. See the
"VxFS Version 5 Disk Layout File System Sizes"
topic in this section for more information. If
bsize is not specified, the block size defaults
are set to the appropriate value, based on size,
when a file system is created.
inosize=n
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.
largefiles|nolargefiles
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_vxf
.
If largefiles is not specified, and inosize is 256
the maximum number of inodes on the file system is
approximately 8,380,000. If largefiles is not
specified, and inosize is 512, the maximum number
of inodes on the file system is approximately
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4,190,000.
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 backup may not
operate correctly if they are not large-file
aware.
logsize=n
n is the number of file system blocks to allocate
for an activity logging area. The minimum value
for the Version 4 and Version 5 disk layout 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.
The default logsize is 16 megabytes for file
systems that are are 512 megabytes or larger. For
a small file system the default may be smaller to
avoid wasting space.
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 small log.
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 swapinfo(1M)).
ninode=n
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.
version=n
n is the VxFS disk layout version number. Valid
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values are 4 and 5. The default is disk layout
Version 5. The Version 5 disk layout supports
file systems up to 32 terabytes in size.
Operands [Toc] [Back]
mkfs recognizes the following operands:
special Name of the special device file for the VxFS file
system.
size The number of sectors in the VxFS file system. See the
"VxFS Version 5 Disk Layout File System Sizes" topic in
this section for more information.
You can specify size 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:
"512 k"
VxFS Version 5 Disk Layout File System Sizes [Toc] [Back]
The Version 5 disk layout supports file systems up to 32 terabytes.
The maximum size of the file system you can create depends on the
block size. (The actual maximum file system size is slightly less
than the maximum values in bytes, described below.)
The following table defines the file system sizes and their associated
values:
------------------------------------------
| Maximum File System Size
------------------------------------------------------
Block Size | In sectors | In bytes
------------------------------------------------------
1024 bytes | 4,294,967,039 | approximately 4 TB
2048 bytes | 8,589,934,078 | approximately 8 TB
4096 bytes | 17,179,868,156 | approximately 16 TB
8192 bytes | 34,359,736,312 | approximately 32 TB
------------------------------------------------------
Note: Sector size (in bytes) is specified by the DEV_BSIZE system
parameter.
RETURN VALUE [Toc] [Back]
mkfs returns the following value:
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0 Successful completion.
1 Command failed due to syntax error.
32 Other error occurred.
EXAMPLES [Toc] [Back]
Use mkfs to create a VxFS file system on /dev/rdsk/c0t6d0:
mkfs -F vxfs /dev/rdsk/c0t6d0 1024
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
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
WARNINGS [Toc] [Back]
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 do not react correctly when confronted with large files.
SEE ALSO [Toc] [Back]
df_vxfs(1M), fsadm_vxfs(1M), fsck_vxfs(1M), mkfs(1M), mount_vxfs(1M),
newfs_vxfs(1M), swapinfo(1M), dir(4), fs_vxfs(4).
Veritas Volume Manager Administrator's Guide
STANDARDS CONFORMANCE [Toc] [Back]
mkfs : SVID3
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