Hi All, I'm working with some disk introspection on KVM, and we trying to create a shadow image of the disk. We've hooked the functions in block.c, in particular bdrv_aio_writev. However we are seeing writes go through, pausing the VM, and the comparing our shadow image with the actual VM image, and they aren't 100% synced up. The first 1-2 sectors appear to be always be correct, however, after that, there are sometimes some discrepancies. I believe we have exhausted most obvious bugs (malloc bugs, incorrect size calculations etc.). Has anyone had any experience with this or have any insights?
Our methodology is as follows: 1. Boot the VM. 2. Pause VM. 3. Copy the disk to our shadow image. 4. Perform very few reads/writes. 5. Pause VM. 6. Compare shadow copy with active vm disk. And this is where we are seeing discrepancies. Any help is much appreciated! We are running on Ubuntu 12.04 with a modified Debian build. - Chad -- Chad S. Spensky MIT Lincoln Laboratory Group 59 (Cyber Systems Assessment) Ph: (781) 981-4173 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
