NAME¶

virt-df - Display free space on virtual filesystems

SYNOPSIS¶

 virt-df [--options]
 virt-df [--options] -d domname
 virt-df [--options] -a disk.img [-a disk.img ...]

Old style:

 virt-df [--options] domname
 virt-df [--options] disk.img [disk.img ...]

DESCRIPTION¶

"virt-df" is a command line tool to display free space on virtual machine filesystems. Unlike other tools, it doesn't just display the size of disk allocated to a virtual machine, but can look inside disk images to see how much space is really being used. If used without any -a or -d arguments, "virt-df" checks with libvirt to get a list of all active and inactive guests, and performs a "df"-type operation on each one in turn, printing out the results. If any -a or -d arguments are specified, "virt-df" performs a "df"-type operation on either the single named libvirt domain, or on the disk image(s) listed on the command line (which must all belong to a single VM). In this mode (with arguments), "virt-df" will only work for a single guest. If you want to run on multiple guests, then you have to invoke "virt-df" multiple times. Use the --csv option to get a format which can be easily parsed by other programs. Other options are similar to the standard df(1) command.

EXAMPLES¶

Show disk usage for a single libvirt guest called "F14x64". Make the output human-readable:

 # virt-df -d F14x64 -h
 Filesystem                       Size     Used  Available  Use%
 F14x64:/dev/sda1                 484M      66M       393M   14%
 F14x64:/dev/vg_f13x64/lv_root    7.4G     3.4G       4.0G   46%

Show disk usage for a disk image file called "test.img":

 $ virt-df -a test1.img
 Filesystem                  1K-blocks     Used  Available  Use%
 test1.img:/dev/sda1             99099     1551      92432    2%

OPTIONS¶

--help

Display brief help.

-a file

--add file

Add file which should be a disk image from a virtual machine. If the virtual machine has multiple block devices, you must supply all of them with separate -a options.

 

The format of the disk image is auto-detected. To override this and force a particular format use the --format=.. option.

-c URI

--connect URI

If using libvirt, connect to the given URI. If omitted, then we connect to the default libvirt hypervisor.

 

If you specify guest block devices directly ( -a), then libvirt is not used at all.

--csv

Write out the results in CSV format (comma-separated values). This format can be imported easily into databases and spreadsheets, but read "NOTE ABOUT CSV FORMAT" below.

-d guest

--domain guest

Add all the disks from the named libvirt guest. Domain UUIDs can be used instead of names.

--format=raw|qcow2|..

--format

The default for the -a option is to auto-detect the format of the disk image. Using this forces the disk format for -a options which follow on the command line. Using --format with no argument switches back to auto-detection for subsequent -a options.

 

For example:

 

 virt-df --format=raw -a disk.img
    

 

forces raw format (no auto-detection) for "disk.img".

 

 virt-df --format=raw -a disk.img --format -a another.img
    

 

forces raw format (no auto-detection) for "disk.img" and reverts to auto-detection for "another.img".

 

If you have untrusted raw-format guest disk images, you should use this option to specify the disk format. This avoids a possible security problem with malicious guests (CVE-2010-3851).

-h

--human-readable

Print sizes in human-readable format.

 

You are not allowed to use -h and --csv at the same time.

-i

--inodes

Print inodes instead of blocks.

--one-per-guest

Run one libguestfs appliance per guest. Normally "virt-df" will add the disks from several guests to a single libguestfs appliance.

 

You might use this option in the following circumstances:

--uuid

Print UUIDs instead of names. This is useful for following a guest even when the guest is migrated or renamed, or when two guests happen to have the same name.

 

Note that only domains that we fetch from libvirt come with UUIDs. For disk images, we still print the disk image name even when this option is specified.

-v

--verbose

Enable verbose messages for debugging.

-V

--version

Display version number and exit.

-x

Enable tracing of libguestfs API calls.

STATVFS NUMBERS¶

"virt-df" (and df(1)) get information by issuing a statvfs(3) system call. You can get the same information directly, either from the host (using libguestfs) or inside the guest:

From the host

Run this command:

 

 guestfish --ro -d GuestName -i statvfs /
    

 

(change "/" to see stats for other filesystems).

From inside the guest

Run this command:

 

 python -c 'import os; s = os.statvfs ("/"); print s'
    

 

(change "/" to see stats for other filesystems).

NOTE ABOUT CSV FORMAT¶

Comma-separated values (CSV) is a deceptive format. It seems like it should be easy to parse, but it is definitely not easy to parse. Myth: Just split fields at commas. Reality: This does not work reliably. This example has two columns:

 "foo,bar",baz

Myth: Read the file one line at a time. Reality: This does not work reliably. This example has one row:

 "foo
 bar",baz

For shell scripts, use "csvtool" (<http://merjis.com/developers/csv> also packaged in major Linux distributions). For other languages, use a CSV processing library (eg. "Text::CSV" for Perl or Python's built-in csv library). Most spreadsheets and databases can import CSV directly.

SHELL QUOTING¶

Libvirt guest names can contain arbitrary characters, some of which have meaning to the shell such as "#" and space. You may need to quote or escape these characters on the command line. See the shell manual page sh(1) for details.

EXIT STATUS¶

This program returns 0 if successful, or non-zero if there was an error.

SEE ALSO¶

df(1), guestfs(3), guestfish(1), virt-filesystems(1), <http://libguestfs.org/>.

AUTHOR¶

Richard W.M. Jones <http://people.redhat.com/~rjones/>

COPYRIGHT¶

Copyright (C) 2009-2012 Red Hat Inc. 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.