RHEV VM gets paused due to "Improbable extension request for volume" error

Issue

• VM went into a Paused state.

• In the vdsm logs on the host running the VM, the following error was repeated every 2 seconds;

periodic/22::ERROR::2016-10-19 15:31:10,727::vm::1000::virt.vm::(_shouldExtendVolume) vmId=`4022b3b2-bb8f-4981-957d-b99d2ddf69bb`::Improbable extension request for volume 39a89cbf-f44c-4401-94ac-e098aa3ad7af on domain c2c235f2-5e61-4cd5-ad5e-9f24b4d3e521, pausing the VM to avoid corruptions (capacity: 80530636800, allocated: 19689451008, physical: 18253611008, next physical size: 19327352832)
periodic/18::ERROR::2016-10-19 15:31:12,742::vm::1000::virt.vm::(_shouldExtendVolume) vmId=`4022b3b2-bb8f-4981-957d-b99d2ddf69bb`::Improbable extension request for volume 39a89cbf-f44c-4401-94ac-e098aa3ad7af on domain c2c235f2-5e61-4cd5-ad5e-9f24b4d3e521, pausing the VM to avoid corruptions (capacity: 80530636800, allocated: 19689451008, physical: 18253611008, next physical size: 19327352832)
...... etc., etc., ......

• In this case, the volume in question was the only volume of the boot disk of a VM, i.e. there were no snapshots.

• When the VM was brought down and restarted, the guest failed to boot.

  • One symptom was a kernel panic.
  • Another was that the kernel was seen to be corrupt, as Grub reported;

"Error 13: Invalid or unsupported executable format"