Abstract: A data storage system can connect a data storage controller to a host and a data storage device. A first reference state corresponding to a first zone of the data storage device can be incremented in response to a first version of data being assigned to the first zone by the data storage controller. A second version of the data may be written to a second zone of the data storage device prior to populating a recently freed list with the first zone having an incorrect reference state. The first zone can be allocated by the data storage controller for new data without altering the incorrect reference state that is subsequently written to the first zone as directed by the data storage controller.

Abstract: Systems and methods are disclosed for multiple duration deduplication entries. A processor may be configured to perform data deduplication operations, including setting a first indicator for first metadata stored to a hash database identifying a first time interval to maintain the first metadata in the database, and setting a second indicator for second metadata stored to the database identifying a second time interval to maintain the second metadata in the database longer than the first time interval. The processor may remove the first metadata from the database when no duplicative data is detected for the first metadata within the first time interval, and remove the second metadata from the database when no duplicative data is detected for the second metadata within the second time interval.

Abstract: Managing a redundant array of independent disks (RAID) storage array involves assigning first and second stripes to span respective first and second sets of disks. A subset of drives in the first set fails such that the first stripe is in a first state wherein a failure of another drive in the first set will lead to data loss in the first stripe. It is determined that the second stripe is in a fault-tolerant state such that the second stripe can have failures of two drives in the second set before the second stripe is in the first state, Part of an operational disk of the second set used by the second stripe is allocated to the first stripe to replace at least part of the subset of failed drives.

Abstract: A data storage system can connect a data storage controller to a host and a data storage device. A first reference state corresponding to a first zone of the data storage device can be incremented in response to a first version of data being assigned to the first zone by the data storage controller. A second version of the data may be written to a second zone of the data storage device prior to populating a recently freed list with the first zone having an incorrect reference state. The first zone can be allocated by the data storage controller for new data without altering the incorrect reference state that is subsequently written to the first zone as directed by the data storage controller.

Abstract: An apparatus may include a controller configured search a hash database storing entries corresponding to hash values of previously stored data to find a hash page of the hash database corresponding to a range of hash values including the first hash value. When the hash page is found, the controller may be configured to determine whether the hash page does not include an entry for the first hash value, the first hash page further including a base hash value for the range of hash values. When the hash page does not include an entry for the first hash value, the controller may be configured to generate a first entry of the first hash page for the first hash value, the first entry including an offset value from the base hash value corresponding to the first hash value and a data location at which the received data is to be stored.

Abstract: Managing a redundant array of independent disks (RAID) storage array involves assigning first and second stripes to span respective first and second sets of disks. A subset of drives in the first set fails such that the first stripe is in a first state wherein a failure of another drive in the first set will lead to data loss in the first stripe. It is determined that the second stripe is in a fault-tolerant state such that the second stripe can have failures of two drives in the second set before the second stripe is in the first state, Part of an operational disk of the second set used by the second stripe is allocated to the first stripe to replace at least part of the subset of failed drives.

Abstract: Policy based data shredding is provided to be executed in a storage controller. A logical volume stored on media, such as magnetic disk drives, may be assigned one or more possible shredding policies. Storing and executing the policies in the controller is more efficient than performing host-based shredding and requires the use of less valuable bandwidth between the host and the controller. In addition, the controller is aware of failures, degradation and offline status of each drive in an array, and is able to thereby terminate or modify a shredding operation if necessary. Each policy includes the number of write passes to be performed on the media location in which the volume is stored and the pattern to write on the media location. The policy may also indicate whether to update a parity area during each of a plurality of write passes or only on the first.

Abstract: An apparatus, system, and method are disclosed for validating logical volume configuration. A determination module makes a determination of a type of a host operating system of a host computer requesting access to a logical volume. A characterization module characterizes the host type of the logical volume. A compatibility module determines if the logical volume is configured for the host operating system. A mitigation module mitigates the mis-configuration if the logical volume is not configured for the host operating system.

Abstract: An apparatus, system, and method are disclosed for accessing management data. A management application program inference stores and retrieves management data in a dedicated management data logical volume of a data storage device. The management data is inaccessible except through the management application program interface. The management data is used to initialize and configure one or more controllers or one or more management nodes for a storage system. The management data logical volume may also be used to consolidate and store process data and to store multiple instances of firmware for the data storage device itself.

Abstract: A method to write information to an information storage medium comprising a plurality of storage blocks interconnected with a networked attached storage device comprising a first file system, a first file system driver, a second file system and a second file system driver. Using the first file system driver, the method opens a file with write permission, and provides a second file comprising the entire first file system. Using the second file system driver, the method locates an Extent Descriptor associated with the file, reads an address from that Extent Descriptor, where the address points to one or more storage blocks disposed in the information storage medium, and determines if any storage blocks have been allocated for the file. In the event no storage blocks have been allocated for the file, the method then allocates one or more storage blocks, and writes the file to those one or more storage blocks.