Storage Technology Corporation

George A Rudeseal

Charles Allen Milligan

Jay S Belsan

Robert F Walsh

Henry S Ludlam

Charles Patrick Schafer

Jeffrey Steven Laughlin

Mark Alan Bakke

Stephen S Selkirk

John Timothy O'Brien

Stephen Henry Blendermann

Steven Michael Halladay

Thomas David West

Steven A Johnson

Paul R Swiatek

Michael C Wojnar

Mogens H Pedersen

John H Bowers

David Grant Beal

Robert H Dunphy, Jr

Patrick James Tomsula

Robert J Raicer

Craig A Buhlman

Fred C Eifert

Alan R Permut

John F Kitchen

Barbara L Steele

A direct access storage system includes at least one disk and a controller. The at least one disk physically may be partitioned into at least one first access performance partition and at least one other access performance partition. The controller may be configured to process I/O accesses to the first access performance partition without regulation and regulate I/O accesses to the at least one other access performance partition.

System and method for quality of service management in a partitioned storage device or subsystem

The intelligent data storage manager functions to combine the non-homogeneous physical devices contained in a data storage subsystem to create a logical device with new and unique quality of service characteristics that satisfy the criteria for the policies appropriate for the present data object. In particular, if there is presently no logical device that is appropriate for use in storing the present data object, the intelligent data storage manager defines a new logical device using existing physical and/or logical device definitions as component building blocks to provide the appropriate characteristics to satisfy the policy requirements. The intelligent data storage manager uses weighted values that are assigned to each of the presently defined logical devices to produce a best fit solution to the requested policies in an n-dimensional best fit matching algorithm. The resulting logical device definition is then implemented by dynamically interconnecting the logical devices that were used as the components of the newly defined logical device to store the data object.

Intelligent data storage manager

One or more background processes that references data storage volumes and cylinders that are to be scrubbed to ensure the integrity of the data stored thereon. A priority scrubbing process is also available to note data storage volumes that have recently had data written thereon by the host processor and which require a more timely review of the data than less frequently used volumes.

Disk scrubbing system

A data storage subsystem dynamically maps a virtual data storage device image presented to associated processors to physical data storage devices used to implement the data storage subsystem. Multiple destage memory elements are concurrently active to increase an aggregate destage data transfer rate and to allow data to be stored on various memory elements appropriate to the type of data contained in each stored virtual object. An open logical cylinder list is used to maintain data integrity among multiple open destage memory elements. Memory elements are also selected to function as archive memory. The data storage subsystem includes a plurality of data storage elements configured into at least two redundancy groups, each redundancy group including n+m of the data storage elements, and a cache memory connected to the redundancy groups and a host processor interface. The data storage subsystem stores data indicative of the amount of available memory space on each of the open logical cylinders and little used data records are migrated or transferred from other memory elements to the archive memory elements to maintain sufficient available memory space.

Dynamically mapped data storage subsystem having multiple open destage

A pair of operationally independent disk drive array data storage subsystems are used to emulate one or more physical devices shared between two control modules. The storage control units of the two data storage subsystems are interconnected by at least one data link to exchange control and data signals therebetween. The storage control units of both data storage subsystems are synchronized to maintain identical virtual device images of certain assigned virtual devices both of the data storage subsystems wherein the duplicated data records of the single virtual device are stored. The data records are therefore stored in available memory on both of the two data storage subsystems. Data is exchanged over the data link to maintain consistency of the two sets of mapping tables.

Fault tolerant disk array data storage subsystem

The data storage subsystem is implemented using an array of data storage elements which vary in data storage characteristics and/or data storage capacity. Control apparatus automatically compensates for any nonuniformity among the data storage elements by selecting a set of physical characteristics that define a common data storage element format. The selected set of physical characteristics may not match any of the disk drives but each disk drive can emulate these selected characteristics. This capability enables the disk drives in the data storage subsystem to be replaced by nonidentical disk drives in a nondisruptive manner to provide continuous data availability.

Disk drive array memory system using nonuniform disk drives

The disk drive array data storage subsystem maps between virtual and physical data storage devices and schedules the writing of data to these devices. The data storage subsystem functions as a conventional large form factor disk drive memory, using an array of redundancy groups, each containing N+M disk drives. This system copies data records by simply creating a duplicate data record pointer in a virtual track directory to reference the original data record. This enables the host processor to access the data record via two virtual addresses while only a single physical copy of the data record resides in the data storage subsystem.

Data record copy system for a disk drive array data storage subsystem

This file server system appears to the host computer to be a plurality of data storage devices which are directly addressable by the host computer using the native data management and access structures of the host computer. The file server however is an intelligent data storage subsystem that defines, manages and accesses synchronized sets of data and maintains these synchronized sets of data external from the host computer system's data management facilities in a manner that is completely transparent to the host computer. This is accomplished by the use of the snapshot application data group that extends the traditional sequential data set processing concept of generation data groups.

File server having snapshot application data groups

The use of a dynamically mapped virtual memory system permits the storage of data so that each data record occupies only the physical space required for the data. Furthermore, the data storage subsystem manages the allocation of physical space on the disk drives and does not rely on the file extent defined in the count key data format. Data compaction apparatus is provided to remove the gaps contained in the stream of count key data records received from the host processor. A data compression algorithm is then used to compress the received data into a compressed format for storage on the disk drives. It is the compacted, compressed data that is finally stored on the disk drives. Furthermore, any data record received from the host processor absent data in the user data field therein is simply listed in the virtual memory map as a null field occupying no physical space on the disk drives. The data storage control, through its mapping capability, stores the actual data in the minimum physical space required by overcoming the limitations imposed on large form factor disk drives by the use of count key data format data records. However, the data storage subsystem returns this stored data to the host processor in count key data format through a data record reformatting process once the stored compacted compressed data is staged to the cache memory for access by the host processor. The data storage subsystem is operationally independent of the host processor, yet performs as if it were a standard operationally dependent large form factor disk subsystem.

Apparatus for compressing data in a dynamically mapped virtual data

This apparatus makes use of a disk drive array to store data records for an associated host processor. This disk drive array emulates the operation of a large form factor disk drive by using a plurality of interconnected small form factor disk drives. These small form factor disk drives are configured into redundancy groups, each of which contains n+m disk drives for storing data records and redundancy information thereon. The use of this configuration is significantly more reliable than a large form factor disk drive. However, in order to maintain compatibility with host processors that request the duplex copy group feature, the phantom duplex copy group apparatus of the present invention mimics the creation of a duplex copy group in this dynamically mapped data storage subsystem using a disk array and a phantom set of pointers that mimic the data storage devices on which the data records are stored.

Phantom duplex copy group apparatus for a disk drive array data storge

The parallel disk drive array data storage subsystem dynamically maps between virtual and physical data storage devices and schedules the writing of data to these devices. The data storage subsystem functions as a conventional large form factor disk drive memory, using an array of redundancy groups, each containing N+M disk drives. The data storage subsystem does not modify data stored in a redundancy group but simply writes the modified data as a new record in available memory space on another redundancy group. The original data is flagged as obsolete. A mapping table is maintained to identify portions of these redundancy groups which contain newly written or modified virtual track instances. These marked virtual track instances are written to backup medium as a background process and the mapping table is updated to clear the flags that identify these virtual track instances as having been modified.

Incremental disk backup system for a dynamically mapped data storage

The deleted dataset space release system provides facilities in a dynamically mapped virtual memory data storage subsystem to immediately release the physical space occupied by a deleted dataset for use by the data storage subsystem to store subsequently received data files. This system also provides data security by preventing the unauthorized access to the data of scratched data files, both in cache memory and on the data storage devices. The deleted dataset space release system utilizes a user exit in the host processor data file scratch routine to transmit information to the data storage subsystem indicative of the host processor data file scratch activity. Existing channel command words are used in a manner that is transparent to the host processor. The data storage subsystem thereby immediately receives an indication that the host processor is scratching a data file from the volume table of contents of a virtual volume. The data storage subsystem can then concurrently scratch this data file from the virtual track directory contained in the data storage subsystem and thereby release the physical storage space occupied by this scratched data file.

Deleted data file space release system for a dynamically mapped virtual

A disk storage system that writes multiple copies of records directed to user-specified volumes. A plurality of spaced apart control units interconnected by direct data links and a corresponding plurality of sets of recording means communicate over the direct data links when a write request is received by one control unit to cause one volume in each set of recording means to write a copy of the received record.

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Boulder, CO, United States of America

George A Rudeseal