NAME
virt-df - 'df'-like utility for virtualization stats
SUMMARY
virt-df [-options]
DESCRIPTION
virt-df is a df(1)-like utility for showing the actual disk usage of
guests. Many command line options are the same as for ordinary *df*.
It uses libvirt so it is capable of showing stats across a variety of
different virtualization systems.
OPTIONS
-a, --all
Show all domains. The default is show only running (active) domains.
-c uri, --connect uri
Connect to libvirt URI. The default is to connect to the default
libvirt URI, normally Xen.
--csv
Print the results in CSV format, suitable for importing into a
spreadsheet or database.
This option is only supported if virt-df was built with CSV support.
--debug
Emit debugging information on stderr. Please supply this if you
report a bug.
-h, --human-readable
Display human-readable sizes (eg. "10GiB" instead of large numbers).
-i, --inodes
Display inode information.
This option only works for Unix-like filesystems.
--help
Display usage summary.
-t diskimage
Test mode. Instead of checking libvirt for domain information, this
runs virt-df directly on the disk image (or device) supplied. You
may specify the -t option multiple times.
--version
Display version and exit.
EXAMPLE
# virt-df
Filesystem 1K-blocks Used Available Type
f9x32kvm:hda1 190740 24817 165923 Linux ext2/3
f9x32kvm:VolGroup/LogVol00 6568348 3401656 3166692 Linux ext2/3
f9x32kvm:VolGroup/LogVol01 1015808 Linux swap
SHORTCOMINGS
virt-df spies on the guest's disk image to try to work out how much disk
space it is actually using. There are some shortcomings to this,
described here.
(1) It only understands a limited set of partition types. Assuming that
the files and partitions that we get back from libvirt / Xen correspond
to block devices in the guests, we can go some way towards manually
parsing those partitions to find out what they contain. We can read the
MBR, LVM, superblocks and so on. However that's a lot of parsing work,
and currently there is no library which understands a wide range of
partition schemes and filesystem types (not even libparted which doesn't
support LVM yet). The Linux kernel does support that, but there's not
really any good way to access that work.
The current implementation uses a hand-coded parser which understands
some formats (MBR, LVM2, ext2/3, DOS FAT, Windows NTFS, Linux swap and
Linux suspend partitions).
(2) The statistics you get are delayed. The real state of, for example,
an ext2 filesystem is only stored in the memory of the guest's kernel.
The ext2 superblock contains some meta-information about blocks used and
free, but this superblock is not up to date. In fact the guest kernel
may not update it even on a 'sync', not until the filesystem is
unmounted. Some operations do appear to write the superblock, for
example fsync(2) [that is my reading of the ext2/3 source code at
least].
SECURITY
The current code tries hard to be secure against malicious guests, for
example guests which set up malicious disk partitions.
SEE ALSO
df(1), virsh(1), xm(1), ,
, ,
AUTHORS
Richard W.M. Jones
COPYRIGHT
(C) Copyright 2007-2008 Red Hat Inc., Richard W.M. Jones
http://libvirt.org/
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
675 Mass Ave, Cambridge, MA 02139, USA.
REPORTING BUGS
Bugs can be viewed on the Red Hat Bugzilla page:
.
If you find a bug in virt-df, please follow these steps to report it:
1. Check for existing bug reports
Go to and search for similar bugs.
Someone may already have reported the same bug, and they may even
have fixed it.
2. Capture debug and error messages
Run
virt-df --debug > virt-df.log 2>&1
and keep *virt-df.log*. It contains error messages which you should
submit with your bug report.
3. Get version of virt-df and version of libvirt.
Run
virt-df --version
4. Submit a bug report.
Go to and enter a new bug. Please
describe the problem in as much detail as possible.
Remember to include the version numbers (step 3) and the debug
messages file (step 2).
5. Assign the bug to rjones @ redhat.com
Assign or reassign the bug to rjones @ redhat.com (without the
spaces). You can also send me an email with the bug number if you
want a faster response.