Storage-assisted quality of service (QoS)
AssigneeInternational Business Machines Corporation
InventorsRonald P. Doyle, David L. Kaminsky, David M. Ogle
Life of this patent
Estimating the term…
Abstract
Storage-Assisted QoS. To provide storage-assisted QoS, a discriminatory storage system able to enforce a service discrimination policy within the storage system can include re-writable media; a storage system controller; a cache; and, a QoS enforcement processor configured to selectively evict entries in the cache according QoS terms propagated into the storage system through the storage system controller.
Claims15
A storage system comprising:
- re-writable media;
- a storage system controller;
- a cache;
- and,
- a Quality of Service (QoS) enforcement processor configured to selectively evict entries in said cache according QoS terms propagated into the storage system through said storage system controller.
In a storage system, a cache eviction method comprising the steps of:
- categorizing entries in a cache according to common Quality of Service (QoS) metrics;
- identifying categorizations whose entries consume an excessive portion of said cache;
- and,
- evicting an entry from among one of said identified categorizations.
A method for enforcing Quality of Service (QoS) terms in a storage system, said method comprising the steps of:
- (A) propagating a QoS metric into the storage system in conjunction with a request to retrieve data from the storage system;
- (B) locating said data in a caching component in the storage system;
- (C) if said data can be located, retrieving said data from said caching component;
- and,
- (D) if said data cannot be located:
- (1) retrieving said data from fixed storage in the storage system,
- (2) determining whether said caching component can accommodate a new cache entry,
- (3) if said caching component cannot accommodate a new cache entry:
- (a) selecting an existing cache entry from among a group of cache entries which share a common QoS metric, but which have consumed more cache then permitted according to said common QoS metric, and,
- (b) evicting said selected cache entry,
- (4) caching said data retrieved from fixed storage in said caching component along with said propagated QoS metric.
A machine readable storage having stored thereon a computer program for performing cache eviction in a storage system, said computer program comprising a routine set of instructions for causing the machine to perform the steps of:
- categorizing entries in a cache according to common Quality of Service (QoS) metrics;
- identifying categorizations whose entries consume an excessive portion of said cache;
- and,
- evicting an entry from among one of said identified categorizations.
A machine readable storage having stored thereon a computer program for enforcing Quality of Service (QoS) terms in a storage system, said computer program comprising a routine set of instructions for causing the machine to perform the steps of:
- (A) propagating a QoS metric into the storage system in conjunction with a request to retrieve data from the storage system;
- (B) locating said data in a caching component in the storage system;
- (C) if said data can be located, retrieving said data from said caching component;
- and,
- (D) if said data cannot be located:
- (1) retrieving said data from fixed storage in the storage system,
- (2) determining whether said caching component can accommodate a new cache entry,
- (3) if said caching component cannot accommodate a new cache entry:
- (a) selecting an existing cache entry from among a group of cache entries which share a common QoS metric, but which have consumed more cache then permitted according to said common QoS metric, and,
- (b) evicting said selected cache entry,
- (4) caching said data retrieved from fixed storage in said caching component along with said propagated QoS metric.
Dependencies are inferred from the claim text.