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6 .TH DF_UFS 1M "Feb 25, 2005"
8 df_ufs \- report free disk space on ufs file systems
12 \fBdf\fR \fB-F\fR ufs [\fIgeneric_options\fR] [\fB-o\fR i] [\fIdirectory\fR | \fIspecial\fR]
18 \fBdf\fR displays the amount of disk space occupied by \fBufs\fR file systems,
19 the amount of used and available space, and how much of the file system's total
20 capacity has been used.The amount of space reported as used and available is
21 less than the amount of space in the file system; this is because the system
22 reserves a fraction of the space in the file system to allow its file system
23 allocation routines to work well. The amount reserved is typically about 10%;
24 this can be adjusted using \fBtunefs\fR(1M). When all the space on the file
25 system except for this reserve is in use, only the superuser can allocate new
26 files and data blocks to existing files. When the file system is overallocated
27 in this way, \fBdf\fR might report that the file system is more than 100%
28 utilized.If neither \fIdirectory\fR nor \fIspecial\fR is specified, \fBdf\fR
29 displays information for all mounted ufs file systems.
33 The following options are supported:
37 \fB\fIgeneric_options\fR\fR
40 Options supported by the generic \fBdf\fR command. See \fBdf\fR(1M) for a
41 description of these options.
50 Specify \fBufs\fR file system specific options. The available option is:
57 Report the number of used and free inodes. This option can not be used with
58 \fIgeneric_options\fR.
67 \fB\fB/etc/mnttab\fR\fR
70 list of file systems currently mounted
76 \fBdf\fR(1M), \fBfsck\fR(1M), \fBfstyp\fR(1M), \fBtunefs\fR(1M),
77 \fBmnttab\fR(4), \fBattributes\fR(5), \fBufs\fR(7FS),
81 \fBdf\fR calculates its results differently for mounted and unmounted file
82 systems. For unmounted systems, the numbers reflect the 10% reservation. This
83 reservation is not reflected in \fBdf\fR output for mounted file systems. For
84 this reason, the available space reported by the generic command can differ
85 from the available space reported by this module.
88 \fBdf\fR might report remaining capacity even though \fBsyslog\fR warns
89 \fBfilesystem full\fR. This issue can occur because \fBdf\fR only uses the
90 available fragment count to calculate available space, but the file system
91 requires contiguous sets of fragments for most allocations.
94 If you suspect that you have exhausted contiguous fragments on your file
95 system, you can use the \fBfstyp\fR(1M) utility with the \fB-v\fR option. In
96 the \fBfstyp\fR output, look at the \fBnbfree\fR (number of blocks free) and
97 \fBnffree\fR (number of fragments free) fields. On unmounted filesystems, you
98 can use \fBfsck\fR(1M) and observe the last line of output, which reports,
99 among other items, the number of fragments and the degree of fragmentation. See