Resizing VirtIO devices

Resizing VirtIO devices

Red Hat Linux Enterprise (RHEL) 6, Update 1 does not support online disk resizing of VirtIO devices. To resize a VirtIO device the guest must be fully shut down and restarted. Support for online resizing of block dvices is under evaluation for RHEL 6, Update 2.

You can use the following methods to resize the devices.

To grow VirtIO devices

Grow the storage.

• If the storage device is a VxVM Volume, re-size the volume.

• If the storage device is a LUN from a storage array, re-size the
  device on the array.

Update the size of the disk device in the host.

• Stop all virtual machines using the storage device.

• If the device is a LUN from a storage array, issue ‘blockdev
  –rereadpt ’ to update the size of the device.

• Restart the virtual machines.

Update the size of the storage device in the guest .

• If VxVM is managing the storage in the guest, use vxdisk resize.

• If VxVM is not managing the storage in the guest, see the appropriate
  documentation.

To shrink guest disk devices

Update the size of the disk device in the guest.

• If VxVM is managing the device in the guest, if necessary, first use
  the vxresize utility to shrink any file systems and volumes which are
  using the device. Use vxdisk resize access_name length=new_size to
  update the size of the public region of the device.

• If VxVM is not managing the storage in the guest, see the appropriate
  documentation.

Shrink the storage in the guest.

• If the device is a VxVM volume, shrink the volume with the vxassist
  utility.

• If the device is a LUN from a storage array, shrink the device on
  storage array.

Update the size of the disk device in the host.

• Stop the guests which are using the devices.

• If the device is a LUN from a storage array, use the blockdev
  –rereadpt device command.

• Start the guests.

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