Managing cache data and metadata

TLDR: In this article, the contents of a non-volatile memory device may be relied upon as accurately reflecting data stored on disk storage across a power transition such as a reboot, and cache metadata may be efficiently accessed and reliably saved and restored across power transitions.

Abstract: Embodiments of the invention provide techniques for ensuring that the contents of a non-volatile memory device may be relied upon as accurately reflecting data stored on disk storage across a power transition such as a reboot. For example, some embodiments of the invention provide techniques for determining whether the cache contents and/or or disk contents are modified during a power transition, causing cache contents to no longer accurately reflect data stored in disk storage. Further, some embodiments provide techniques for managing cache metadata during normal ("steady state") operations and across power transitions, ensuring that cache metadata may be efficiently accessed and reliably saved and restored across power transitions.