KVM Image Jammed After Power Unplug-Collection of common programming errors

We have a HP DL380 Server which has ubuntu 12.04 OS as Host and for Virtualization KVM. Power of our server unplugged suddenly and after plugging power size of image of vm in

*/var/lib/libvirt/images/image.img*

decreased from 100G to 1G and when vm power up following error occurred:

error: unknown filesystem grub rescue>

we had critical data on vm so what should we do ?

So, you put “critical data” on a server with no backups (and from the sounds of things), no battery or NVRAM-backed write cache, and no UPS?

You might, maybe, be able to get some professional data recovery help and pay thousands of dollars to have that critical data back in a few weeks, but in the general case:

You’re screwed. The only thing you can do is learn a lesson (or two) from this. To wit.

1. Data you don’t backup is data you don’t care about. If you have data you care about, you back it up.

2. Power matters. Plug your servers into UPS(es), employ battery or flash-backed write caches, and control physical access to your servers and their power sources.

3. An ounce of prevention is worth a pound of cure. The prevention route’s cheaper too.