A data storage system which automatically provides and maintains identical secondary data on a preferably geographically remote secondary data storage device. The system includes a primary host computer located in the first geographic location which is coupled to a primary data storage system also located in the first geographic location. The primary data storage system includes at least one primary data storage device on which primary data is to be stored, and a primary data storage system controller which receives data from the primary host computer and controls the storing of the primary data on the primary data storage device. The primary data storage controller is coupled by high speed communication link to a secondary data storage system controller of a secondary data storage system, and coordinates the copying of the primary data to the secondary data storing system, and is responsive to an acknowledgement from the secondary data storage system controller of at least successful receipt of the primary data for updating the maintained list of the primary data to indicate that the copied primary data has been received by the secondary data storage system to be copied to the secondary data storage device.

Remote data mirroring

Two data storage systems are interconnected by a data link for remote mirroring of data. Each volume of data is configured as local, primary in a remotely mirrored volume pair, or secondary in a remotely mirrored volume pair. Normally, a host computer directly accesses either a local or a primary volume, and data written to a primary volume is automatically sent over the data link to a corresponding secondary volume. The host computer sends chains of channel commands to the data storage system containing a primary (R1) volume of a remotely mirrored volume pair. In order to more effectively use the capacity of the data link, the data storage system containing the primary (R1) volume bundles the write data for all write commands in the chain into a single write command for transmission over the data link to the secondary data storage system containing the secondary (R2) volume. The data storage system containing the primary (R1) volume decodes the channel commands to determine when it has received the last channel command in the chain, and once the last channel command in the chain is received, it transmits the bundle of write data for the chain over the data link to the data storage system containing the secondary (R2) volume. In a preferred implementation, the write data is stored in a cache memory in the data storage system containing the primary (R1) volume, and the data storage system containing the primary (R1) volume bundles the write data by accumulating, in a buffer, pointers to the write data in the cache memory.

Bundling of write data from channel commands in a command chain for transmission over a data link between data storage systems for remote data mirroring

Data storage system controlled remote data mirroring with respectively maintained data indices

A peer-to-peer (P2P) probing/network quality of service (QoS) analysis system utilizes a UDP-based probing tool for determining latency, bandwidth, and packet loss ratio between peers in a network. The probing tool enables network QoS probing between peers that connect through a network address translator. The list of peers to probe is provided by a connection server based on prior probe results and an estimate of the network condition. The list includes those peers which are predicted to have the best QoS with the requesting peer. Once the list is obtained, the requesting peer probes the actual QoS to each peer on the list, and returns these results to the connection server. P2P probing in parallel using a modified packet-pair scheme is utilized. If anomalous results are obtained, a hop-by-hop probing scheme is utilized to determine the QoS of each link. In such a scheme, differential destination measurement is utilized.

Peer-To-Peer Method of Quality of Service (QoS) Probing and Analysis and Infrastructure Employing Same

A data mapping architecture for mapping between two or more data sources without modifying the metadata or structure of the data sources themselves. Data mapping also supports updates. The architecture also supports at least the case where data sources that are being mapped, are given, their schemas predefined, and cannot be changed. The architecture includes a mapping component that receives respective metadata from at least two arbitrary data models, and maps expressions between the data models.

Mapping architecture for arbitrary data models

With detection of a selected error event involving a data storage drive and data storage media, a subsystem attempts to move the media to another drive, and conduct a similar operation. The subsystem separately tracks successive error events of individual drives and individual media, wherein a complete successful operation breaks the chain of the successive error events; and upon the number of successive error events reaching a threshold, fails the data storage drive or the data storage media. Error events are categorized into:
 1) error events before or during a mount of a media into a drive; and 2) error events after a successful mount of a media into a drive; and
 
conducts the tracking, comparing and failing steps separately for each of the categories for the drives and the media.

Tracking error events relating to data storage drives and/or media of automated data storage library subsystems

An automated data storage library stores logical volumes, including logical volumes to be copied to a second library, in cache storage, and migrates logical volumes to physical media volumes stored on storage shelves. In response to a request for recalling one of the logical volumes to be copied to cache, a library controller first determines which physical media volume contains the requested migrated logical volume. The library controller identifies all of the logical volumes to be copied that are migrated and stored as stacked logical volumes on the physical media volume containing the requested migrated logical volume; selects up to “N” of the identified logical volumes, including the requested migrated logical volume; and may arrange a selection list of the selected logical volumes in a sequence in accordance with the order that the logical volumes are written on the physical media volume. The selected logical volumes are then recalled to cache storage, and a list of the recalled logical volumes is provided in response to the recall request.

Recalling logical volumes to cache from physical media volumes for redundant storage in automated data storage libraries

Disclosed is a system, typically implemented in a storage controller, for extracting data from a device storing data in a first format, such as the count-key-data (CKD) format. The first format is comprised of a plurality of tracks. Each track has at least one data area and each data area is comprised of at least one addressable block of data. A request from a host system for an address of a block of data in a second data format, such as the Fixed Block Architecture (FBA) format, is received. The system calculates a byte displacement value for the requested address. A data area in a track in the device having a byte displacement value less than the byte displacement value for the requested address is located. A byte location offset is then determined by subtracting the byte displacement value for the located data area from the byte displacement value for the requested address. The system then determines a location in the located data area of a block of data at the byte location offset. The system then provides the host system with the located block of data.

Data sharing between system using different data storage formats

An apparatus, system, and method are disclosed for recalling a logical volume from a mountable media for use in a virtual tape server. The apparatus includes a receiving module, a queuing module, and an optimizer module. The receiving module receives recall requests for logical volumes stored in a mountable media such as a tape cartridge. The queuing module places the requests in a queue to be processed in turn. The optimizer module reorders the queue based on one or more optimization rules in order to process the recall requests more efficiently.

Apparatus, system, and method for optimizing recall of logical volumes in a virtual tape server

A method, system, apparatus and computer program product for determining an optimal file operational time in a data storage system for use with a tape media storing data in a serpentine pattern on tape media is provided. The operational time is optimized based on a “sequence on tape” algorithm, a “minimum reversal of direction on tape” algorithm, or a “minimum delay to next data” algorithm. A model is used to determine the predicted performance of each of the algorithms, and the algorithm that provides the minimum overall operational time is chosen and applied for carrying out an operational process on the tape media.

Keith Anthony Bello

Papers

Tracking error events relating to data storage drives and/or media of automated data storage library subsystems

Recalling logical volumes to cache from physical media volumes for redundant storage in automated data storage libraries

Data sharing between system using different data storage formats

Apparatus, system, and method for optimizing recall of logical volumes in a virtual tape server

Optimizing operational requests of logical volumes