DF_UFS(8) Maintenance Commands and Procedures DF_UFS(8)

NAME

df_ufs - report free disk space on ufs file systems

SYNOPSIS

df -F ufs [generic_options] [-o i] [directory | special]

DESCRIPTION

df displays the amount of disk space occupied by ufs file systems,
the amount of used and available space, and how much of the file
system's total capacity has been used.The amount of space reported as
used and available is less than the amount of space in the file
system; this is because the system reserves a fraction of the space
in the file system to allow its file system allocation routines to
work well. The amount reserved is typically about 10%; this can be
adjusted using tunefs(8). When all the space on the file system
except for this reserve is in use, only the superuser can allocate
new files and data blocks to existing files. When the file system is
overallocated in this way, df might report that the file system is
more than 100% utilized.If neither directory nor special is
specified, df displays information for all mounted ufs file systems.

OPTIONS

The following options are supported:

generic_options
Options supported by the generic df command. See
df(8) for a description of these options.


-o
Specify ufs file system specific options. The
available option is:

i
Report the number of used and free inodes.
This option can not be used with
generic_options.

FILES

/etc/mnttab
list of file systems currently mounted

SEE ALSO

df(8), fsck(8), fstyp(8), tunefs(8), mnttab(5), attributes(7),
ufs(4FS),

NOTES

df calculates its results differently for mounted and unmounted file
systems. For unmounted systems, the numbers reflect the 10%
reservation. This reservation is not reflected in df output for
mounted file systems. For this reason, the available space reported
by the generic command can differ from the available space reported
by this module.


df might report remaining capacity even though syslog warns
filesystem full. This issue can occur because df only uses the
available fragment count to calculate available space, but the file
system requires contiguous sets of fragments for most allocations.


If you suspect that you have exhausted contiguous fragments on your
file system, you can use the fstyp(8) utility with the -v option. In
the fstyp output, look at the nbfree (number of blocks free) and
nffree (number of fragments free) fields. On unmounted filesystems,
you can use fsck(8) and observe the last line of output, which
reports, among other items, the number of fragments and the degree of
fragmentation. See fsck(8).

February 25, 2005 DF_UFS(8)