DF_UFS(8) Maintenance Procedures DF_UFS(8)


df_ufs - report free disk space on ufs file systems


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


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


The following options are supported:

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

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

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


list of file systems currently mounted


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


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)