Retention of active data stored in memory

摘要

A method and apparatus for retention of active data stored in memory using multiple indexing systems for data storage. An embodiment of a method for retention of active data in a storage server includes reading data into a first location of a main memory of the storage server. The data in the first location indexes data elements in a long-term data storage in a first manner. The method further provides for copying the data from the first location into a second location in the main memory of the storage server, where the data in the second location indexing the data elements in the long-term data storage in a second manner.

主权项

1. A method comprising:
in response to receiving a mirror update to a second storage volume from a first storage volume to mirror a change in a first storage server,
storing, by a destination storage server, active data from a first location in a memory of the destination storage server to a second location in the memory, wherein the first location is in a data cache that stores cached data elements of a storage device of the destination storage server, and wherein the second location stores a metadata structure indexing the data elements of the second storage volume, andunmounting the second storage volume to perform the mirror update, wherein the unmounting invalidates the active data at the first location due to its inclusion in the data cache but does not invalidate the metadata structure stored at the second location; and providing a requested data element to a client upon request, wherein providing the requested data element comprises:
checking the metadata structure in the memory for the requested data element when the requested data element is not found in the data cache of the memory, andwhen the requested data element is in the metadata structure, copying the requested data element to a third location in the memory that is part of the data cache from the metadata structure to make the requested data element available for the client.