2 virt-df - 'df'-like utility for virtualization stats
8 virt-df is a df(1)-like utility for showing the actual disk usage of
9 guests. Many command line options are the same as for ordinary *df*.
11 It uses libvirt so it is capable of showing stats across a variety of
12 different virtualization systems.
16 Show all domains. The default is show only running (active) domains.
19 Connect to libvirt URI. The default is to connect to the default
20 libvirt URI, normally Xen.
23 Print the results in CSV format, suitable for importing into a
24 spreadsheet or database.
26 This option is only supported if virt-df was built with CSV support.
29 Emit debugging information on stderr. Please supply this if you
33 Display human-readable sizes (eg. "10GiB" instead of large numbers).
36 Display inode information.
38 This option only works for Unix-like filesystems.
41 Display usage summary.
44 Test mode. Instead of checking libvirt for domain information, this
45 runs virt-df directly on the disk image (or device) supplied. You
46 may specify the -t option multiple times.
49 Display version and exit.
53 Filesystem 1K-blocks Used Available Type
54 f9x32kvm:hda1 190740 24817 165923 Linux ext2/3
55 f9x32kvm:VolGroup/LogVol00 6568348 3401656 3166692 Linux ext2/3
56 f9x32kvm:VolGroup/LogVol01 1015808 Linux swap
59 virt-df spies on the guest's disk image to try to work out how much disk
60 space it is actually using. There are some shortcomings to this,
63 (1) It only understands a limited set of partition types. Assuming that
64 the files and partitions that we get back from libvirt / Xen correspond
65 to block devices in the guests, we can go some way towards manually
66 parsing those partitions to find out what they contain. We can read the
67 MBR, LVM, superblocks and so on. However that's a lot of parsing work,
68 and currently there is no library which understands a wide range of
69 partition schemes and filesystem types (not even libparted which doesn't
70 support LVM yet). The Linux kernel does support that, but there's not
71 really any good way to access that work.
73 The current implementation uses a hand-coded parser which understands
74 some formats (MBR, LVM2, ext2/3, DOS FAT, Windows NTFS, Linux swap and
75 Linux suspend partitions).
77 (2) The statistics you get are delayed. The real state of, for example,
78 an ext2 filesystem is only stored in the memory of the guest's kernel.
79 The ext2 superblock contains some meta-information about blocks used and
80 free, but this superblock is not up to date. In fact the guest kernel
81 may not update it even on a 'sync', not until the filesystem is
82 unmounted. Some operations do appear to write the superblock, for
83 example fsync(2) [that is my reading of the ext2/3 source code at
87 The current code tries hard to be secure against malicious guests, for
88 example guests which set up malicious disk partitions.
91 df(1), virsh(1), xm(1), <http://www.libvirt.org/ocaml/>,
92 <http://www.libvirt.org/>, <http://et.redhat.com/~rjones/>,
93 <http://caml.inria.fr/>
96 Richard W.M. Jones <rjones @ redhat . com>
99 (C) Copyright 2007-2008 Red Hat Inc., Richard W.M. Jones
102 This program is free software; you can redistribute it and/or modify it
103 under the terms of the GNU General Public License as published by the
104 Free Software Foundation; either version 2 of the License, or (at your
105 option) any later version.
107 This program is distributed in the hope that it will be useful, but
108 WITHOUT ANY WARRANTY; without even the implied warranty of
109 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
110 Public License for more details.
112 You should have received a copy of the GNU General Public License along
113 with this program; if not, write to the Free Software Foundation, Inc.,
114 675 Mass Ave, Cambridge, MA 02139, USA.
117 Bugs can be viewed on the Red Hat Bugzilla page:
118 <https://bugzilla.redhat.com/>.
120 If you find a bug in virt-df, please follow these steps to report it:
122 1. Check for existing bug reports
123 Go to <https://bugzilla.redhat.com/> and search for similar bugs.
124 Someone may already have reported the same bug, and they may even
127 2. Capture debug and error messages
130 virt-df --debug > virt-df.log 2>&1
132 and keep *virt-df.log*. It contains error messages which you should
133 submit with your bug report.
135 3. Get version of virt-df and version of libvirt.
140 4. Submit a bug report.
141 Go to <https://bugzilla.redhat.com/> and enter a new bug. Please
142 describe the problem in as much detail as possible.
144 Remember to include the version numbers (step 3) and the debug
145 messages file (step 2).
147 5. Assign the bug to rjones @ redhat.com
148 Assign or reassign the bug to rjones @ redhat.com (without the
149 spaces). You can also send me an email with the bug number if you
150 want a faster response.