Provided by: libguestfs-tools_1.24.5-1ubuntu0.1_amd64 bug

NAME

       virt-resize - Resize a virtual machine disk

SYNOPSIS

        virt-resize [--resize /dev/sdaN=[+/-]<size>[%]]
          [--expand /dev/sdaN] [--shrink /dev/sdaN]
          [--ignore /dev/sdaN] [--delete /dev/sdaN] [...] indisk outdisk

DESCRIPTION

       Virt-resize is a tool which can resize a virtual machine disk, making it larger or smaller
       overall, and resizing or deleting any partitions contained within.

       Virt-resize cannot resize disk images in-place.  Virt-resize should not be used on live
       virtual machines - for consistent results, shut the virtual machine down before resizing
       it.

       If you are not familiar with the associated tools: virt-filesystems(1) and virt-df(1), we
       recommend you go and read those manual pages first.

EXAMPLES

       1.  Copy "olddisk" to "newdisk", extending one of the guest's partitions to fill the extra
           5GB of space.

            virt-filesystems --long -h --all -a olddisk

            truncate -r olddisk newdisk
            truncate -s +5G newdisk

            # Note "/dev/sda2" is a partition inside the "olddisk" file.
            virt-resize --expand /dev/sda2 olddisk newdisk

       2.  As above, but make the /boot partition 200MB bigger, while giving the remaining space
           to /dev/sda2:

            virt-resize --resize /dev/sda1=+200M --expand /dev/sda2 \
              olddisk newdisk

       3.  As in the first example, but expand a logical volume as the final step.  This is what
           you would typically use for Linux guests that use LVM:

            virt-resize --expand /dev/sda2 --LV-expand /dev/vg_guest/lv_root \
              olddisk newdisk

       4.  As in the first example, but the output format will be qcow2 instead of a raw disk:

            qemu-img create -f qcow2 -o preallocation=metadata newdisk.qcow2 15G
            virt-resize --expand /dev/sda2 olddisk newdisk.qcow2

DETAILED USAGE

   EXPANDING A VIRTUAL MACHINE DISK
       1. Shut down the virtual machine
       2. Locate input disk image
           Locate the input disk image (ie. the file or device on the host containing the guest's
           disk).  If the guest is managed by libvirt, you can use "virsh dumpxml" like this to
           find the disk image name:

            # virsh dumpxml guestname | xpath /domain/devices/disk/source
            Found 1 nodes:
            -- NODE --
            <source dev="/dev/vg/lv_guest" />

       3. Look at current sizing
           Use virt-filesystems(1) to display the current partitions and sizes:

            # virt-filesystems --long --parts --blkdevs -h -a /dev/vg/lv_guest
            Name       Type       Size  Parent
            /dev/sda1  partition  101M  /dev/sda
            /dev/sda2  partition  7.9G  /dev/sda
            /dev/sda   device     8.0G  -

           (This example is a virtual machine with an 8 GB disk which we would like to expand up
           to 10 GB).

       4. Create output disk
           Virt-resize cannot do in-place disk modifications.  You have to have space to store
           the resized output disk.

           To store the resized disk image in a file, create a file of a suitable size:

            # rm -f outdisk
            # truncate -s 10G outdisk

           Or use lvcreate(1) to create a logical volume:

            # lvcreate -L 10G -n lv_name vg_name

           Or use virsh(1) vol-create-as to create a libvirt storage volume:

            # virsh pool-list
            # virsh vol-create-as poolname newvol 10G

       5. Resize
           virt-resize takes two mandatory parameters, the input disk (eg. device, file, or a URI
           to a remote disk) and the output disk.  The output disk is the one created in the
           previous step.

            # virt-resize indisk outdisk

           This command just copies disk image "indisk" to disk image "outdisk" without resizing
           or changing any existing partitions.  If "outdisk" is larger, then an extra, empty
           partition is created at the end of the disk covering the extra space.  If "outdisk" is
           smaller, then it will give an error.

           More realistically you'd want to expand existing partitions in the disk image by
           passing extra options (for the full list see the "OPTIONS" section below).

           "--expand" is the most useful option.  It expands the named partition within the disk
           to fill any extra space:

            # virt-resize --expand /dev/sda2 indisk outdisk

           (In this case, an extra partition is not created at the end of the disk, because there
           will be no unused space).

           "--resize" is the other commonly used option.  The following would increase the size
           of /dev/sda1 by 200M, and expand /dev/sda2 to fill the rest of the available space:

            # virt-resize --resize /dev/sda1=+200M --expand /dev/sda2 \
                indisk outdisk

           If the expanded partition in the image contains a filesystem or LVM PV, then if virt-
           resize knows how, it will resize the contents, the equivalent of calling a command
           such as pvresize(8), resize2fs(8), ntfsresize(8) or btrfs(8).  However virt-resize
           does not know how to resize some filesystems, so you would have to online resize them
           after booting the guest.

            # virt-resize --expand /dev/sda2 nbd://example.com outdisk

           The input disk can be a URI, in order to use a remote disk as the source.  The URI
           format is compatible with guestfish.  See "ADDING REMOTE STORAGE" in guestfish(1).

           Other options are covered below.

       6. Test
           Thoroughly test the new disk image before discarding the old one.

           If you are using libvirt, edit the XML to point at the new disk:

            # virsh edit guestname

           Change <source ...>, see http://libvirt.org/formatdomain.html#elementsDisks

           Then start up the domain with the new, resized disk:

            # virsh start guestname

           and check that it still works.  See also the "NOTES" section below for additional
           information.

       7. Resize LVs etc inside the guest
           (This can also be done offline using guestfish(1))

           Once the guest has booted you should see the new space available, at least for
           filesystems that virt-resize knows how to resize, and for PVs.  The user may need to
           resize LVs inside PVs, and also resize filesystem types that virt-resize does not know
           how to expand.

   SHRINKING A VIRTUAL MACHINE DISK
       Shrinking is somewhat more complex than expanding, and only an overview is given here.

       Firstly virt-resize will not attempt to shrink any partition content (PVs, filesystems).
       The user has to shrink content before passing the disk image to virt-resize, and virt-
       resize will check that the content has been shrunk properly.

       (Shrinking can also be done offline using guestfish(1))

       After shrinking PVs and filesystems, shut down the guest, and proceed with steps 3 and 4
       above to allocate a new disk image.

       Then run virt-resize with any of the --shrink and/or --resize options.

   IGNORING OR DELETING PARTITIONS
       virt-resize also gives a convenient way to ignore or delete partitions when copying from
       the input disk to the output disk.  Ignoring a partition speeds up the copy where you
       don't care about the existing contents of a partition.  Deleting a partition removes it
       completely, but note that it also renumbers any partitions after the one which is deleted,
       which can leave some guests unbootable.

   QCOW2 AND NON-SPARSE RAW FORMATS
       If the input disk is in qcow2 format, then you may prefer that the output is in qcow2
       format as well.  Alternately, virt-resize can convert the format on the fly.  The output
       format is simply determined by the format of the empty output container that you provide.
       Thus to create qcow2 output, use:

        qemu-img create [-c] -f qcow2 -o preallocation=metadata outdisk [size]

       instead of the truncate command (use -c for a compressed disk).

       Similarly, to get non-sparse raw output use:

        fallocate -l size outdisk

       (on older systems that don't have the fallocate(1) command use "dd if=/dev/zero of=outdisk
       bs=1M count=..")

   LOGICAL PARTITIONS
       Logical partitions (a.k.a. "/dev/sda5+" on disks using DOS partition tables) cannot be
       resized.

       To understand what is going on, firstly one of the four partitions "/dev/sda1-4" will have
       MBR partition type 05 or "0f".  This is called the extended partition.  Use
       virt-filesystems(1) to see the MBR partition type.

       Logical partitions live inside the extended partition.

       The extended partition can be expanded, but not shrunk (unless you force it, which is not
       advisable).  When the extended partition is copied across, all the logical partitions
       contained inside are copied over implicitly.  Virt-resize does not look inside the
       extended partition, so it copies the logical partitions blindly.

       You cannot specify a logical partition ("/dev/sda5+") at all on the command line.  Doing
       so will give an error.

OPTIONS

       --help
           Display help.

       --align-first auto
       --align-first never
       --align-first always
           Align the first partition for improved performance (see also the --alignment option).

           The default is --align-first auto which only aligns the first partition if it is safe
           to do so.  That is, only when we know how to fix the bootloader automatically, and at
           the moment that can only be done for Windows guests.

           --align-first never means we never move the first partition.  This is the safest
           option.  Try this if the guest does not boot after resizing.

           --align-first always means we always align the first partition (if it needs to be
           aligned).  For some guests this will break the bootloader, making the guest
           unbootable.

       --alignment N
           Set the alignment of partitions to "N" sectors.  The default in virt-resize < 1.13.19
           was 64 sectors, and after that is 128 sectors.

           Assuming 512 byte sector size inside the guest, here are some suitable values for
           this:

           --alignment 1 (512 bytes)
               The partitions would be packed together as closely as possible, but would be
               completely unaligned.  In some cases this can cause very poor performance.  See
               virt-alignment-scan(1) for further details.

           --alignment 8 (4K)
               This would be the minimum acceptable alignment for reasonable performance on
               modern hosts.

           --alignment 128 (64K)
               This alignment provides good performance when the host is using high end network
               storage.

           --alignment 2048 (1M)
               This is the standard alignment used by all newly installed guests since around
               2008.

       -d
       --debug
           (Deprecated: use -v option instead)

           Enable debugging messages.

       --debug-gc
           Debug garbage collection and memory allocation.  This is only useful when debugging
           memory problems in virt-resize or the OCaml libguestfs bindings.

       --delete part
           Delete the named partition.  It would be more accurate to describe this as "don't copy
           it over", since virt-resize doesn't do in-place changes and the original disk image is
           left intact.

           Note that when you delete a partition, then anything contained in the partition is
           also deleted.  Furthermore, this causes any partitions that come after to be
           renumbered, which can easily make your guest unbootable.

           You can give this option multiple times.

       --expand part
           Expand the named partition so it uses up all extra space (space left over after any
           other resize changes that you request have been done).

           If virt-resize knows how, it will expand the direct content of the partition.  For
           example, if the partition is an LVM PV, it will expand the PV to fit (like calling
           pvresize(8)).  Virt-resize leaves any other content it doesn't know about alone.

           Currently virt-resize can resize:

           •   ext2, ext3 and ext4 filesystems.

           •   NTFS filesystems, if libguestfs was compiled with support for NTFS.

               The filesystem must have been shut down consistently last time it was used.
               Additionally, ntfsresize(8) marks the resized filesystem as requiring a
               consistency check, so at the first boot after resizing Windows will check the
               disk.

           •   LVM PVs (physical volumes).  virt-resize does not usually resize anything inside
               the PV, but see the --LV-expand option.  The user could also resize LVs as desired
               after boot.

           •   Btrfs filesystems, if libguestfs was compiled with support for btrfs.

           Note that you cannot use --expand and --shrink together.

       --format raw
           Specify the format of the input disk image.  If this flag is not given then it is
           auto-detected from the image itself.

           If working with untrusted raw-format guest disk images, you should ensure the format
           is always specified.

           Note that this option does not affect the output format.  See "QCOW2 AND NON-SPARSE
           RAW FORMATS".

       --ignore part
           Ignore the named partition.  Effectively this means the partition is allocated on the
           destination disk, but the content is not copied across from the source disk.  The
           content of the partition will be blank (all zero bytes).

           You can give this option multiple times.

       --LV-expand logvol
           This takes the logical volume and, as a final step, expands it to fill all the space
           available in its volume group.  A typical usage, assuming a Linux guest with a single
           PV "/dev/sda2" and a root device called "/dev/vg_guest/lv_root" would be:

            virt-resize indisk outdisk \
              --expand /dev/sda2 --LV-expand /dev/vg_guest/lv_root

           This would first expand the partition (and PV), and then expand the root device to
           fill the extra space in the PV.

           The contents of the LV are also resized if virt-resize knows how to do that.  You can
           stop virt-resize from trying to expand the content by using the option
           --no-expand-content.

           Use virt-filesystems(1) to list the filesystems in the guest.

           You can give this option multiple times, but it doesn't make sense to do this unless
           the logical volumes you specify are all in different volume groups.

       --machine-readable
           This option is used to make the output more machine friendly when being parsed by
           other programs.  See "MACHINE READABLE OUTPUT" below.

       -n
       --dryrun
           Print a summary of what would be done, but don't do anything.

       --no-copy-boot-loader
           By default, virt-resize copies over some sectors at the start of the disk (up to the
           beginning of the first partition).  Commonly these sectors contain the Master Boot
           Record (MBR) and the boot loader, and are required in order for the guest to boot
           correctly.

           If you specify this flag, then this initial copy is not done.  You may need to
           reinstall the boot loader in this case.

       --no-extra-partition
           By default, virt-resize creates an extra partition if there is any extra, unused space
           after all resizing has happened.  Use this option to prevent the extra partition from
           being created.  If you do this then the extra space will be inaccessible until you run
           fdisk, parted, or some other partitioning tool in the guest.

           Note that if the surplus space is smaller than 10 MB, no extra partition will be
           created.

       --no-expand-content
           By default, virt-resize will try to expand the direct contents of partitions, if it
           knows how (see --expand option above).

           If you give the --no-expand-content option then virt-resize will not attempt this.

       --no-sparse
           Turn off sparse copying.  See "SPARSE COPYING" below.

       --ntfsresize-force
           Pass the --force option to ntfsresize(8), allowing resizing even if the NTFS disk is
           marked as needing a consistency check.  You have to use this option if you want to
           resize a Windows guest multiple times without booting into Windows between each
           resize.

       --output-format raw
           Specify the format of the output disk image.  If this flag is not given then it is
           auto-detected from the image itself.

           If working with untrusted raw-format guest disk images, you should ensure the format
           is always specified.

           Note that this option does not create the output format.  This option just tells
           libguestfs what it is so it doesn't try to guess it.  You still need to create the
           output disk with the right format.  See "QCOW2 AND NON-SPARSE RAW FORMATS".

       -q
       --quiet
           Don't print the summary.

       --resize part=size
           Resize the named partition (expanding or shrinking it) so that it has the given size.

           "size" can be expressed as an absolute number followed by b/K/M/G to mean bytes,
           Kilobytes, Megabytes, or Gigabytes; or as a percentage of the current size; or as a
           relative number or percentage.  For example:

            --resize /dev/sda2=10G

            --resize /dev/sda4=90%

            --resize /dev/sda2=+1G

            --resize /dev/sda2=-200M

            --resize /dev/sda1=+128K

            --resize /dev/sda1=+10%

            --resize /dev/sda1=-10%

           You can increase the size of any partition.  Virt-resize will expand the direct
           content of the partition if it knows how (see --expand below).

           You can only decrease the size of partitions that contain filesystems or PVs which
           have already been shrunk.  Virt-resize will check this has been done before
           proceeding, or else will print an error (see also --resize-force).

           You can give this option multiple times.

       --resize-force part=size
           This is the same as --resize except that it will let you decrease the size of any
           partition.  Generally this means you will lose any data which was at the end of the
           partition you shrink, but you may not care about that (eg. if shrinking an unused
           partition, or if you can easily recreate it such as a swap partition).

           See also the --ignore option.

       --shrink part
           Shrink the named partition until the overall disk image fits in the destination.  The
           named partition must contain a filesystem or PV which has already been shrunk using
           another tool (eg. guestfish(1) or other online tools).  Virt-resize will check this
           and give an error if it has not been done.

           The amount by which the overall disk must be shrunk (after carrying out all other
           operations requested by the user) is called the "deficit".  For example, a straight
           copy (assume no other operations) from a 5GB disk image to a 4GB disk image results in
           a 1GB deficit.  In this case, virt-resize would give an error unless the user
           specified a partition to shrink and that partition had more than a gigabyte of free
           space.

           Note that you cannot use --expand and --shrink together.

       -v
       --verbose
           Enable debugging messages.

       -V
       --version
           Display version number and exit.

MACHINE READABLE OUTPUT

       The --machine-readable option can be used to make the output more machine friendly, which
       is useful when calling virt-resize from other programs, GUIs etc.

       There are two ways to use this option.

       Firstly use the option on its own to query the capabilities of the virt-resize binary.
       Typical output looks like this:

        $ virt-resize --machine-readable
        virt-resize
        ntfsresize-force
        32bitok
        ntfs
        btrfs

       A list of features is printed, one per line, and the program exits with status 0.

       Secondly use the option in conjunction with other options to make the regular program
       output more machine friendly.

       At the moment this means:

       1.  Progress bar messages can be parsed from stdout by looking for this regular
           expression:

            ^[0-9]+/[0-9]+$

       2.  The calling program should treat messages sent to stdout (except for progress bar
           messages) as status messages.  They can be logged and/or displayed to the user.

       3.  The calling program should treat messages sent to stderr as error messages.  In
           addition, virt-resize exits with a non-zero status code if there was a fatal error.

       Versions of the program prior to 1.13.9 did not support the --machine-readable option and
       will return an error.

NOTES

   "Partition 1 does not end on cylinder boundary."
       Virt-resize aligns partitions to multiples of 128 sectors (see the --alignment parameter).
       Usually this means the partitions will not be aligned to the ancient CHS geometry.
       However CHS geometry is meaningless for disks manufactured since the early 1990s, and
       doubly so for virtual hard drives.  Alignment of partitions to cylinders is not required
       by any modern operating system.

   GUEST BOOT STUCK AT "GRUB"
       If a Linux guest does not boot after resizing, and the boot is stuck after printing "GRUB"
       on the console, try reinstalling grub.

        guestfish -i -a newdisk
        ><fs> cat /boot/grub/device.map
        # check the contents of this file are sensible or
        # edit the file if necessary
        ><fs> grub-install / /dev/vda
        ><fs> exit

       For more flexible guest reconfiguration, including if you need to specify other parameters
       to grub-install, use virt-rescue(1).

   RESIZING WINDOWS BOOT PARTITIONS
       In Windows Vista and later versions, Microsoft switched to using a separate boot
       partition.  In these VMs, typically "/dev/sda1" is the boot partition and "/dev/sda2" is
       the main (C:) drive.  Resizing the first (boot) partition causes the bootloader to fail
       with 0xC0000225 error.  Resizing the second partition (ie. C: drive) should work.

   WINDOWS CHKDSK
       Windows disks which use NTFS must be consistent before virt-resize can be used.  If the
       ntfsresize operation fails, try booting the original VM and running "chkdsk /f" on all
       NTFS partitions, then shut down the VM cleanly.  For further information see:
       https://bugzilla.redhat.com/show_bug.cgi?id=975753

       After resize Windows may initiate a lengthy "chkdsk" on first boot if NTFS partitions have
       been expanded.  This is just a safety check and (unless it find errors) is nothing to
       worry about.

   WINDOWS UNMOUNTABLE_BOOT_VOLUME BSOD
       After sysprepping a Windows guest and then resizing it with virt-resize, you may see the
       guest fail to boot with an "UNMOUNTABLE_BOOT_VOLUME" BSOD.  This error is caused by having
       "ExtendOemPartition=1" in the sysprep.inf file.  Removing this line before sysprepping
       should fix the problem.

   WINDOWS 8
       Windows 8 "fast startup" can prevent virt-resize from resizing NTFS partitions.  See
       "WINDOWS HIBERNATION AND WINDOWS 8 FAST STARTUP" in guestfs(3).

   SPARSE COPYING
       You should create a fresh, zeroed target disk image for virt-resize to use.

       Virt-resize by default performs sparse copying.  This means that it does not copy blocks
       from the source disk which are all zeroes.  This improves speed and efficiency, but will
       produce incorrect results if the target disk image contains unzeroed data.

       The main time this can be a problem is if the target is a host partition (eg.
       "virt-resize source.img /dev/sda4") because the usual partitioning tools tend to leave
       whatever data happened to be on the disk before.

       If you have to reuse a target which contains data already, you should use the --no-sparse
       option.  Note this can be much slower.

ALTERNATIVE TOOLS

       There are several proprietary tools for resizing partitions.  We won't mention any here.

       parted(8) and its graphical shell gparted can do some types of resizing operations on disk
       images.  They can resize and move partitions, but I don't think they can do anything with
       the contents, and they certainly don't understand LVM.

       guestfish(1) can do everything that virt-resize can do and a lot more, but at a much lower
       level.  You will probably end up hand-calculating sector offsets, which is something that
       virt-resize was designed to avoid.  If you want to see the guestfish-equivalent commands
       that virt-resize runs, use the --debug flag.

       dracut(8) includes a module called "dracut-modules-growroot" which can be used to grow the
       root partition when the guest first boots up.  There is documentation for this module in
       an associated README file.

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

       virt-filesystems(1), virt-df(1), guestfs(3), guestfish(1), lvm(8), pvresize(8),
       lvresize(8), resize2fs(8), ntfsresize(8), btrfs(8), virsh(1), parted(8), truncate(1),
       fallocate(1), grub(8), grub-install(8), virt-rescue(1), virt-sparsify(1),
       virt-alignment-scan(1), http://libguestfs.org/.

AUTHOR

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

COPYRIGHT

       Copyright (C) 2010-2012 Red Hat Inc.

LICENSE

       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.

BUGS

       To get a list of bugs against libguestfs, use this link:
       https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools

       To report a new bug against libguestfs, use this link:
       https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools

       When reporting a bug, please supply:

       •   The version of libguestfs.

       •   Where you got libguestfs (eg. which Linux distro, compiled from source, etc)

       •   Describe the bug accurately and give a way to reproduce it.

       •   Run libguestfs-test-tool(1) and paste the complete, unedited output into the bug
           report.