Data migration between multiple tiers in a storage system using policy based ILM for QOS

摘要

Technologies are described for implementing a default migration mechanism in a storage system containing multiple tiers of storage with each tier having different cost and performance parameters. Data that is accessed more frequently can be migrated toward higher performance storage tiers while data that is accessed less frequently can be migrated towards lower performance storage tiers. Default migration behavior can be overridden by user-specified values for tier age residency policy, demotion policy, tier occupancy of volumes, and tier assignment. Data migration can be paused by the user and resumed by the user.

主权项

1. A method for managing a tiered storage system, the method comprising:
providing a default policy for associating logical drives with tiers based on a set of predetermined factors, wherein each tier has different cost and performance parameters; assigning at least two of the logical drives to a same tier based on the default policy; receiving a user-specified tier for one of the at least two of the logical drives assigned to the same tier; assigning the one of the at least two of the logical drives to the user-specified tier, wherein the user-specified tier is different than the same tier with which the at least two of the logical drives are associated based on the default policy; imposing a hierarchy on the tiers; providing a default policy for data migration based on an age or frequency of access of data, the default policy comprising respective default migration ages or respective default migration frequencies of access for each of the tiers; and moving data from a current tier to a destination tier in the hierarchy in response to the data being stored in the current tier for a period of time greater than the respective default migration age or greater than the respective default migration frequency of access.