Emc Corporation

Arod Shatil

Timothy M Mulvihill

George S Maloof, Jr

Edith Epstein

Moshe Schreiber

Stephen A Ludlum

Haim Avni

Stefano Sguazzin

Eric Paul Johnson

Mechanisms and techniques allow a host computer system to control memory management techniques within a data storage system. The host computer system can detect a requirement of the computer system to access data in the data storage system and can identify a data access policy based on the requirement of the computer system to access data. The host can then include, within a data access request, a data access policy identifier that corresponds to the identified data access policy. The host then transmits the data access request including the data access policy identifier to the data storage system. The data storage system receives the data access request and selects a data access policy based on the data access policy identifier. The selected data access policy defining a memory management technique to use within the data storage system. The data storage system configures itself to operate according to the memory management technique and services the data access request according to the data access policy.

Methods and apparatus for controlling access to data in a data storage system

A service processor has a memory, and a controller coupled to the memory. The controller is configured to perform part of a maintenance procedure on a data storage system such that a state of the data storage system transitions from a first state to a second state, and store, in a memory, a data structure identifying the second state. The controller is further configured to, after the maintenance procedure is aborted prior to completion of the maintenance procedure and after a transition of the state of the data storage system from the second state to a third state, (i) restore the data storage system to the second state based on the data structure stored in the memory, and (ii) complete the maintenance procedure.

Methods and apparatus for performing a maintenance procedure on a data storage system

Mechanisms and techniques allow a host computer system to control caching operations within a data storage system. In a typical implementation, the system of the invention operates within a host computer system to intercept requests for access to data stored within a data storage system that originate from applications, programs or other processes that perform (e.g., execute) on the host computer system or another computer system. Once intercepted, the host computer can examine such a request for access to data to determine if the request matches any prefetch criteria defined within a prefetch database provided by the system of the invention. As an example, prefetch criteria defined in a prefetch database can specify various requestors (e.g., applications, programs, processes, users, or the like) that can access data (e.g., specific files, databases, volumes, data types or the like) stored within the data storage system according to various data access techniques (e.g., filesystems command such as open, read, write, seek and so forth). If a request for access to data matches prefetch criteria, the host computer configured with the invention determines prefetch information for related data related to data specified in the request based on the matching prefetch criteria. The prefetch information indicates the manner (e.g., amount, permanence, etc.) in which related data is to be cached in the data storage system. The host computer also obtains storage information for the related data that indicates the location of the related data stored within the data storage system. Using the prefetch information and the storage information, the invention generates one or more prefetch commands which indicate what related data is to be cached within the data storage system and from what storage locations within the data storage system that related data is to be obtained. The prefetch command is then transmitted to the data storage system to cause the data storage system to cache the related data.

Methods and apparatus for providing host controlled caching of data in a storage system

A storage system is provided which includes an internal local area network. The local area network is achieved by providing a separate Ethernet bus as well as Ethernet hardware on each host and disk/tape controller within the storage system. Each host controller and disk/tape controller is coupled to the Ethernet bus via the Ethernet interface hardware. Also coupled to the Ethernet bus is a service processor. The service processor is coupled to the Ethernet bus via an Ethernet hub. All communications between the service processor and the controllers occurs over the Ethernet bus. This allows communications with the controllers which does not materially impact the operation of the storage system in providing storage services to the attached host computers.

Storage system with internal LAN

A method and apparatus is provided for detecting airborne particles in an electronic enclosure. The electronic enclosure may be used to house one or more electronic devices or components of an electronic system, such as a computer or data storage system. A particle detection system is provided to monitor the air within the enclosure and to generate an alarm signal in response to detection of a threshold level of airborne particles within the enclosure that is indicative of an operational anomaly associated with at least one of the electronic devices or components. In response to the alarm signal, the electronic devices housed within the enclosure may be automatically shut down to reduce potential damage to at least the devices housed within the enclosure. The detection system is particularly suited for detecting the presence of smoke within an electronic enclosure, such as may be generated during a combustion event by overheated or electrically shorted electronic components.

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Chestnut Hill, MA, United States of America

Arod Shatil