Abstract:
Apparatus and method for highly efficient data queries. In accordance with various embodiments, a data structure is provided in a memory space with a first portion characterized as a virtual data space storing non-sequential entries and a second portion characterized as a first data array of sequential entries. At least a first sequential entry of the data array points to a skip list, at least a second sequential entry of the data array points to a second data array, and at least a third sequential entry points to a selected non-sequential entry in the first portion.
Abstract:
A directory structure for a sparsely filled data container comprises a linked list, doubly linked list, skip list, or other non-fully populated list technique. One or more hierarchical levels of such lists may be used for sparsely filled directories. The directory structure may be converted to a conventional look-up table directory by reconstructing the directory when the directory becomes populated to certain point.
Abstract:
Apparatus and associated method that stores first metadata only at the same addressable storage location of a computer readable medium as that where associated first user data is stored, and afterward satisfies a read request for the first user data by retrieving the first user data from the addressable location of the computer readable medium where the first metadata is stored if the first metadata has a first value, and by reconstructing the first user data from other metadata stored at another addressable location of the computer readable medium than where the first metadata is stored if the first metadata has a second value.
Abstract:
Metadata architecture and associated methodology for a data storage system employing a grid-based storage capacity wherein each grid defines a storage unit in terms of a plurality of storage domains along one axis against one or more rows of a plurality of storage stripes along another axis, and wherein a grid grouping of two or more grids defines a sheet of data storage capacity. The metadata comprises identification information stored in a memory space characterizing an allocation status of the sheets in the storage capacity. A method is provided for allocating memory for the grid-based storage capacity comprising determining whether the allocation is associated with an existing logical device. If the determining step is associated with an existing logical device, then a logical device allocation map and a sheet allocation table are accessed to allocate a selected storage unit. Otherwise, a sheet allocation descriptor and a sheet allocation map are accessed to allocate a selected storage unit. A method is provided for transferring data for the grid-based storage capacity comprising accessing a logical device allocation map and a drive organization table to transfer data to or from a selected storage unit.
Abstract:
Apparatus and method for accessing a virtual storage space. The space is arranged across a plurality of storage elements, and a skip list is used to map as individual nodes each of a plurality of non-overlapping ranges of virtual block addresses of the virtual storage space from a selected storage element.
Abstract:
A data storage system is provided comprising memory allocation information associated with a change in a system configuration of memory allocation within a memory space, and means for updating the system configuration by saving the memory allocation information before updating the system configuration. A recovery record comprises memory allocation information associated with the change in system configuration of memory allocation, and a completion indicator comprises a first value if the memory allocation information is included in the system configuration and comprises a second value if the memory allocation information is not included in the system configuration.
Abstract:
Method and apparatus for adaptive arrangement of data on storage media, such as in a multi-device storage array across which data are stored. A virtual hot space is formed to store frequently accessed data. The virtual hot space comprises at least one hot data zone which extends across storage media of a plurality of arrayed storage devices over a selected seek range less than an overall radial width of the media. The frequently accessed data are stored to the hot data zone(s) in response to a host level request, such as from a host level operating system (OS) or by a user which identifies the data as frequently accessed data. Alternatively or additionally, access statistics are accumulated and frequently accessed data are migrated to the hot data zone(s) in relation thereto. Lower accessed data sets are further preferably migrated from the hot data zone(s) to another location of the media.
Abstract:
Provided herein is a method and apparatus for host transparent storage controller failover and failback. A controller is capable of assuming the identity of a failed controller while continuing to respond to its own SCSI ID or IDs in such a way that all SCSI IDs and associated units (LUNS) of the failed controller are effectively taken over by the surviving controller. This "failover" behavior is transparent to any attached host computers and is treated by such attached hosts as a powerfail condition. The symmetric operation of returning the targets (IDs) and units (LUNs) to the previously failing controller ("failback") is likewise transparent.
Abstract:
Method and apparatus for adaptive arrangement of data on storage media, such as in a multi-device storage array across which data are stored. A virtual hot space is formed to store frequently accessed data. The virtual hot space comprises at least one hot data zone which extends across storage media of a plurality of arrayed storage devices over a selected seek range less than an overall radial width of the media. The frequently accessed data are stored to the hot data zone(s) in response to a host level request, such as from a host level operating system (OS) or by a user which identifies the data as frequently accessed data. Alternatively or additionally, access statistics are accumulated and frequently accessed data are migrated to the hot data zone(s) in relation thereto. Lower accessed data sets are further preferably migrated from the hot data zone(s) to another location of the media.
Abstract:
An apparatus and associated method are provided for performing a storage transaction associated with a network I/O command by employing an ASIC having an interconnect selectively coupling a plurality of dedicated purpose function controllers in the ASIC to a policy processor via a list manager in the ASIC communicating on a peripheral device bus to which the policy processor is connected.