Netapp, Inc.

David Lively

Narayan Venkat

Kenny Speer

A method and system of persistent cache invalidation ensures cache durability. A storage filter driver of a storage input/output (I/O) stack of a server may be used to capture (i.e., track) write requests made to storage devices prior to the persistent cache becoming operational. Entries in the cache having overlapping address ranges with the tracked write requests may be invalidated before the cache is deemed operational. In this manner, the cache remains consistent with the backing store across the administrative actions or failure event (albeit with less valid entries). Notably, the filter driver tracks (i.e., captures) metadata of the write request (i.e., address range and size of the request) to support invalidation of matching cache entries. As such, the filter driver need not store (record) data associated with the write request.

Method to persistent invalidation to ensure cache durability

Described herein is a system and method for maintaining cache coherency. The system and method may maintain coherency for a cache memory that is coupled to a plurality of primary storage devices. The system and method may write data to the cache memory and associate the data with a cache generation identification (ID). A different cache generation ID may be associated with each new set of data that is written to the cache memory. The cache generation ID may be written to the primary storage devices. A backup restore operation may be performed on one of the primary storage devices and a backup restore notification may be received. In response to the notification, the system and method may compare the cache generation ID with the generation ID stored on the restored primary storage device and invalidate data stored on the cache memory for the restored primary storage device.

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Hudson, MA, United States of America

David Lively