Background Snapshots in QEMU: Towards Asynchronous Revert
summary
Prototype implements background snapshot in QEMU using Linux 5.7’s write-protect and userfaultfd-style page tracking, streaming a disk state while the VM runs and capturing memory changes via copy-on-write patches. The tool saves full disk state and incremental memory patches to an external stream and performs revert with only a few milliseconds of downtime in tests. Several kernel and QEMU patches exist; work-in-progress shows successful async reverts on single-disk VMs.
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chapters (11)
- 0:00Background snapshots in QEMU
- 1:51Snapshot limitations and downtime
- 4:02Linux kernel 5.7 feature
- 6:01Asynchronous revert benefits
- 8:09Compatibility and challenges
- 10:24Memory state transfer
- 12:56Implementation progress
- 14:29Downtime optimization
- 16:00Guest state access problems
- 17:34Tracking memory access
- 19:06Future work
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