mkfs(1M_SFS) (SFS) mkfs(1M_SFS)
NAME
mkfs (sfs) - construct a sfs file system
SYNOPSIS
mkfs [-F sfs] [generic_options] [-o specific_options] special [size]
DESCRIPTION
generic_options are options supported by the generic mkfs
command. current_options are options supported by the s5-
specific module of the mkfs command.
mkfs constructs a file system by writing on the special file
special unless the `-o N' flag has been specified. The
numeric size specifies the number of logical 512 byte sectors
in the file system. mkfs builds a file system with a root
directory and a lost+found directory [see fsck(1M)]. The
number of inodes is calculated as a function of the file
system size.
The options are:
-F sfs Specifies the sfs-FSType.
-o Specify the sfs specific options. These options can be
specified in any order, but must be separated by
commas. The following options are available:
M Specifies that the root of the file system is to
be a multilevel directory.
N Do not write the file system to the special file.
This suboption gives all the information needed
to create a file system but does not create it.
nsect=n
n is the number of sectors per track on the
disk. The default is 18.
ntrack=n
n is the number of tracks per cylinder on the
disk. The default is 9.
bsize=n
The primary block size for files on the file
system. n must be a power of two, currently
selected from 2048 or 8192 (the default). The
Copyright 1994 Novell, Inc. Page 1
mkfs(1M_SFS) (SFS) mkfs(1M_SFS)
default block size will be the same as the
machine page size, unless the page size is less
than 2048, in which case the default block size
is 2048.
fragsize=n
The fragment size for files on the file system.
n represents the smallest amount of disk space
that will be allocated to a file. It must be a
power of two currently selected from the range
512 to 8192. The default fragment size will
equal the block size if the block size is less
than or equal to 2048; otherwise, it is 1024.
cgsize=n
The number of disk cylinders per cylinder group.
n must be in the range 1 to 32. cgsize has
different defaults, depending on the size of the
cylinder group. If the cylinder group is less
than 3/4 MB, cgsize defaults to 16. If the
cylinder group is between 3/4 and 1.5 MB,
cgsize defaults to 12. If the cylinder group is
greater than 1.5 MB, cgsize defaults to 8.
rps=n n is the rotational speed of the disk, in
revolutions per second. The default is 60.
nbpi=n n is the number of bytes for which one inode
block is allocated. This parameter is currently
set at one inode block for every 1024 bytes.
opt=s|t
Space or time optimization preference; s
specifies optimization for space, t specifies
optimization for time. The default is t.
apc=n n is the number of alternates per cylinder (SCSI
devices only). The default is 0.
gap=n n is the expected time (in milliseconds) to
service a transfer completion interrupt and
initiate a new transfer on the same disk. It is
used to decide how much rotational spacing to
place between successive blocks in a file. The
default is 4.
Copyright 1994 Novell, Inc. Page 2
mkfs(1M_SFS) (SFS) mkfs(1M_SFS)
C Some applications that pre-date SVR4 do not work
on file systems with more than 64K inodes.
Therefore, when the number of inodes for the
file system being built exceeds the 64K limit,
mkfs prompts the user to confirm that he or she
indeed wants the large number of inodes. The -o
C option silences this mkfs prompt and limits
the number of inodes to a maximum of 64K,
ensuring perfect binary compatibility with the
pre-Release 4 UNIX System.
L When the number of inodes for the file system
being built exceeds the 64K limit, mkfs prompts
the user to confirm that he or she indeed wants
the large number of inodes. The -o L option
silences this prompt and allows the user to
create a file system with more than 64K inodes.
special
mkfs constructs a file system by writing on the special
file.
size Specify the number of logical 512 byte sectors in the
file system. The largest file size is a maximum of
4,194,304 512-byte sectors (2 gigbytes).
NOTICES
The number of inodes is calculated as a function of the file
system size, but can be modified with the nbpi option. For
those who want a file system suitable for lots of tiny files
(smaller than one block), the nbpi parameter may be used to
increase the number of inodes.
You should keep a note of spare superblock copies in the ufs
file system, so that in the event of superblock corruption,
you will know which blocks contain spare entries.
REFERENCES
dirent(4), sfs-specific fs(4SFS), fsck(1M), generic mkfs(1M)
Copyright 1994 Novell, Inc. Page 3