How to persist the data to files and restore them when VM reboot?

[UNKJay]

Hi maintainer
I want to persist the data to files and restore them when VM reboot, how can I do that? Do you have some ideas or guides for me?
Thank you so much.

[huaicheng]

Good question! Persisting the data to files should be straightforward to do, consider following the following tips:

• Ultimately, what needs to be done is writing the FEMU backend DRAM buffer (SsdDramBackend->logical_space) to a file.
• You might also want to persist the FTL status (e.g. mapping table and metadata to record the page status, etc.) if you are using the Blackbox mode, or the OOB buffers for OCSSD mode
• When to trigger the data persistence operations? Better do it at a place right before the QEMU main() loop exits.
• When to load your persisted data structures from files? At FEMU initialization phase, you can replace the logic to fill relevant data structures with data read from files, rather than defaulting to zeros.

[UNKJay]

Thank you!!! I'll have a try