International Business Machines Corporation

Brian D Hatfield

Lokesh M Gupta

Kurt Allen Lovrien

Matthew Sanchez

Ellen Joanne Grusy

Theresa Mary Brown

Michael T Benhase

Gail Andrea Spear

Nicolas Marc Clayton

Theodore Timothy Harris, Jr

Lei Liu

David Brent Schreiber

Wenjeng Ko

Carol Santich Mellgren

Raul Eduardo Saba

Matthew G Borlick

Richard Anthony Ripberger

Oladimeji O Omoniyi

Travis Janssen

Runyu Jin

Matthew John Ward

Joshua J Crawford

Douglas William Dewey

William Griswold Sherman

Scott A Brewer

Ivan Ronald Olguin, Ii

Bradley J Smith

Travis Jannsen

An embodiment includes detecting, by a Recovery System, a cache metric where the cache metric comprises a probability of access to a data object for each of a plurality of time segments of a failover log, where the probability of access to the data object for each of the plurality of time segments is based on an access time of the data object contained in the failover log. The embodiment also includes responsive to receiving the cache metric, caching by the Recovery System of the data object based on the cache metric where the data object is cached in a standby cache of the Recovery System.

Application recovery accelerator

An embodiment enables a first machine to receive an asynchronous data update from a second machine, the asynchronous data update comprising a first stream of identifiers and a second stream of data, wherein the first stream of identifiers comprises a first identifier corresponding to a first data segment in the second stream of data. An embodiment analyzes, as a part of the asynchronous data update, the first stream of identifiers. An embodiment determines at a first time, responsive to the analyzing, that the first data segment corresponding to the first identifier has not arrived at the first machine by the first time. An embodiment updates, responsive to the determining at the first time, a record at the first machine with the first identifier. An embodiment updates the record at a second time, responsive to receiving the first data segment at the first machine at the second time.

Data replica change analysis

Aspects of the present disclosure relate to file system delta visualization. A primary data set and a secondary data set can be received. A difference between the primary data set and the secondary data set can be determined. A determination can be made that a condition is met for file system delta visualization. The difference between the primary data set and the secondary data set can be visualized within a file system delta visualization representation.

File system delta visualization

A computer-implemented method according to one embodiment includes obtaining a first latch for a first node within a tree data structure; copying a first version number of the first node; unlatching the first node; copying the first node; latching the first node a second time after completing the copying; copying a second version number of the first node; and performing one or more actions in response to a comparison of the first version number and the second version number.

Performing a write-prioritized tree copy

In one aspect of write sort management in accordance with the present disclosure, a write sort task related to write sorting a write list of data units to be destaged to storage, is assigned to a storage controller to improve the load balance among plural storage controllers. In one embodiment, available processing capacities of each of the storage controllers is determined by, for example, polling each of the storage controllers. A write sort task may then be assigned to a selected storage controller as a function of determined available processing capacities of each of the storage controllers to improve the load balance among the storage controllers. Other aspects and advantages are provided, depending upon the particular application.

Write sort management in a multiple storage controller data storage system

In one aspect of write sort management in accordance with the present disclosure, a sort/no-sort determination is made prior to issuing to a write command to a target storage controller. The write command identifies a write data unit such track write data, for example, of a first write list of write data units to be written to storage locations of storage. The write command further identifies the storage location at which the write data unit of the first write list is to be stored. In one embodiment, the sort/no-sort determination determines whether an insertion point for an entry in a target write list is to be determined as a function of a write list search such as a logarithmic time search for a write list sort. As a result, the write list search for a write list sort, may be selectively either performed or bypassed for insertion of the target write list entry as a function of the sort/no-sort determination Other aspects and advantages are provided, depending upon the particular application.

Systems and methods for storing nodes, preferably, leaf nodes, of a data tree structure into storage are disclosed, and in one or more aspects restoring the leaf nodes from storage, preferably to memory. Copying the nodes into storage includes in an embodiment share-latching a first node of a data tree to be copied; copying the first node that is share-latched into storage; determining if there is a sibling second node linked to the first node; following a link between the first copied node and the sibling second node, share-latching the sibling second node, unlatching the first copied node, and copying the sibling second node into storage. Restoring includes copying the leaf nodes from storage, updating the leaf nodes, and creating/recreating the data tree.

Data tree checkpoint and restoration system and method

Provided are a computer program product, system, and method for establishing reverse paths between servers in a copy environment. A path establish request operation is initiated to establish paths between a first system and a second system for a copy relationship to copy data from a first storage to a second storage managed by the second system. In response to the path establish request, a pair of ports is established at the first system and the second system to use for a first path from the first system to the second system. The first system sends a reverse path establish request to establish a second path from the second system to the first system, wherein the second system sends messages to the first system on the second path for the copy relationship.

Establishing paths between servers in a copy environment for different copy relationships between the servers

A computer-implemented method according to one embodiment includes creating a single data log; storing data from a plurality of different data streams in at least one data unit of the single data log; and allocating an additional data unit to the single data log in response to one or more criteria.

Aggregating separate data within a single data log wherein single data log is divided in a plurality of blocks assigned to plurality of different streams

Establishing reverse paths between servers in a copy environment

Provided are a computer program product, system, and method for replicating tracks from a first storage to a second and third storages. A determination is made of a track in the first storage to transfer to the second storage as part of a point-in-time copy relationship and of a stride of tracks including the target track. The stride of tracks including the target track is staged from the first storage to a cache according to the point-in-time copy relationship. The staged stride is destaged from the cache to the second storage. The stride in the cache is transferred to the third storage as part of a mirror copy relationship. The stride of tracks in the cache is demoted in response to destaging the stride of the tracks in the cache to the second storage and transferring the stride of tracks in the cache to the third storage.

Replicating tracks from a first storage site to a second and third storage sites

Systems and methods for initializing a memory system are provided. One system includes a processor and a memory including a storage volume coupled to the processor. The storage volume includes a first bitmap for tracking an initialization process for the storage volume and a second bitmap for tracking a copying process for the storage volume. A method includes performing, via the processor, an initialization process for the storage volume and tracking, via the processor utilizing the first bitmap, the initialization process. The method further includes performing, via the processor, a copying process for the storage volume prior to completing the initialization process and tracking, via the processor utilizing the second bitmap, the copying process. Also provided are computer storage mediums including computer program code for performing the above method.

Systems and methods for initializing a memory system

Provided are a computer program product, system, and method for using inactive copy relationships to resynchronize data between storages. A first and second groups of active copy relationships are established to serially copy data among the storages in the first and second groups, respectively. At least one of the storages in both the first group and the second group comprise overlapping storages that are members of both the first and second groups and at least one of the storages in both the first and second groups comprise non-overlapping storages that are a member of only one of the first and second groups. At least one inactive copy relationship is established having as a source storage one of the non-overlapping storages in the first group and as a target storage one of the non-overlapping storages in the second group.

Using inactive copy relationships to resynchronize data between storages

Provided are a computer program product, system, and method for using queues corresponding to attribute values associated with units of work to select the units of work to process. A plurality of queues for each of a plurality of attribute types of attributes are associated with the units of work to process, wherein there are queues for different possible attribute values for each of the attribute types. A unit of work to process is received. A determination is made for each of the attribute types at least one of the queues corresponding to at least one attribute value for the attribute type associated with the received unit of work. A record for the received unit of work is added to each of the determined queues.

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Tucson, AZ, United States of America

Brian D Hatfield