News Column

Patent Application Titled "Point in Time Copy Operations from Source Volumes to Space Efficient Target Volumes in Two Stages via a Non-Volatile...

August 26, 2014



Patent Application Titled "Point in Time Copy Operations from Source Volumes to Space Efficient Target Volumes in Two Stages via a Non-Volatile Storage" Published Online

By a News Reporter-Staff News Editor at Information Technology Newsweekly -- According to news reporting originating from Washington, D.C., by VerticalNews journalists, a patent application by the inventors Brown, Theresa M. (Tucson, AZ); Francisco, Nedlaya Y. (Tucson, AZ); Li, Suguang (Tucson, AZ); Peterson, Beth A. (Tucson, AZ), filed on February 5, 2013, was made available online on August 14, 2014.

The assignee for this patent application is International Business Machines Corporation.

Reporters obtained the following quote from the background information supplied by the inventors: "The disclosure relates to a method, system, and article of manufacture for performing point in time copy operations from source volumes to space efficient target volumes in two stages via a non-volatile storage.

"A storage controller may be coupled to one or more of a plurality of hosts. The storage controller may manage a plurality of storage devices, such as disk drives, tape drives, etc., that are coupled to the storage controller. The plurality of hosts may access data stored in the storage devices via the storage controller.

"The storage controller may provide point in time, full volume copies of data, with the copies available for read or write access. A point in time copy is a fully usable copy of a defined collection of data that contains an image of the data at a single point in time. The copy is considered to have logically occurred at that point in time, but implementations may perform part or all of the copy to a target storage device at other times as long as the result is a consistent copy of the data as it appeared at that point in time. It may be noted that the physical copy is considered complete at the point at which all the tracks in a copy relationship are copied to disks or other storage devices on the target.

"Point in time copy operations create a copy of a source volume on the target volume. The copy is called a point in time copy. When a point in time copy operation is initiated, a point in time copy relationship is created between a source volume and target volume. A point in time copy relationship is a mapping of the source volume and a corresponding target volume. This mapping allows a point in time copy of that source volume to be copied to the corresponding target volume.

"In certain situations, the target volumes are space efficient volumes. In space efficient volumes, the space for volumes are allocated when the point in time copy operations actually copies tracks, extents, blocks, or other storage units to the target volumes. Without space efficient target volumes, the point in time copy operation may require that all the space on a target volume be allocated and be available even if no data is copied to the target volumes. With space efficient volumes, a point in time copy operation uses only the number of tracks that are required to write the data that is changed during the lifetime of the point in time relationship, so the allocation of space is on an as needed basis. While the target volume, in certain situations may need to be of the same size or larger in size in comparison to the source volume (as full volume copies need to allow for the maximum extents required by the size of the source volume), in many situations the space used or provisioned for the target volume may only be a fraction of the source volume. As a result, the point in time copy operation with space efficient target volumes increases the potential for a more effective use of system storage capacity."

In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventors' summary information for this patent application: "Provided are a method, a system, and a computer program product in which a request is received to perform a point in time copy operation from a source volume to a space efficient target volume. A controller copies data stored in a group of data storage units, from the source volume to a non-volatile storage, to preserve the point in time copy operation. A background process asynchronously copies the data from the non-volatile storage to the space efficient target volume to commit a physical point in time copy of the data from the source volume to the target volume.

"In additional embodiments, the copying from the source volume to the non-volatile storage avoids performing of operations to allocate space in the space efficient target volume before responding to the request that the point in time operation is complete, wherein the performing of operations to allocate space in the space efficient target volume is performed while asynchronously copying the data via the background process from the non-volatile storage to the space efficient target volume.

"In further embodiments, the space efficient target volume is a track space efficient target volume, an extent space efficient target volume, or is based on any other representation of storage that is different from tracks or extents. In certain additional embodiments, a request to perform a write operation to a source volume is received, and in response to determining that the asynchronous copying of the data via the background process is not complete but a corresponding point in time data is present in the non-volatile storage, the write operation on the source volume is performed.

"In certain embodiments, a request is received to perform a read operation on a selected space efficient target volume. In response to determining that the asynchronous copying of the data via the background process is complete, the read operation is responded to from the space efficient target volume.

"In certain additional embodiments, in response to determining that the asynchronous copying of the data via the background process is in progress, a determination is made as to whether the read operation can be responded to from the non-volatile storage. In response to determining that the read operation can be responded to from the non-volatile storage, the read operation is responded to from the non-volatile storage. In response to determining that the read operation cannot be responded to from the non-volatile storage, the read operation is responded to from the source volume corresponding to the selected space efficient target volume.

"In additional embodiments, the data storage units correspond to tracks, and groups of tracks are copied to the non-volatile storage during source destage intercept. The asynchronous copying further comprises destaging a track from the non-volatile storage to the space efficient target volume, updating a bitmap metadata to indicate that the track has been copied to the space efficient target volume, and demoting the track from the non-volatile storage.

BRIEF DESCRIPTION OF THE. DRAWINGS

"Referring now to the drawings in which like reference numbers represent corresponding parts throughout:

"FIG. 1 illustrates a block diagram of a computing environment that includes a storage controller coupled to a host and one or more storage devices, in accordance with certain embodiments;

"FIG. 2 illustrates a block diagram that shows point in time copy operations for copying to space efficient target volumes in two stages, in accordance with certain embodiments;

"FIG. 3A illustrates flowchart that shows how responses are made to a request received for a read operation from a space efficient target volume, in accordance with certain embodiments;

"FIG. 3B illustrates flowchart that shows how responses are made to a request received for a write operation, in accordance with certain embodiments;

"FIG. 4 illustrates a flowchart that shows how asynchronous copy operations are performed via the background process, in accordance with certain embodiments;

"FIG. 5 illustrates a flowchart that shows certain operations related to point in time copy operations, in accordance with certain embodiments;

"FIG. 6 illustrates a block diagram with programmatic steps that show single track grouping for source destage intercept in case of standard volumes and space efficient target volumes, in accordance with certain embodiments;

"FIG. 7 illustrates a block diagram with programmatic steps that show how writing is performed to non volatile storage for a group of tracks in case of space efficient target volumes, in accordance with certain embodiments; and

"FIG. 8 illustrates a block diagram of a computational system that shows certain elements that may be included in at least the storage controllers of FIG. 1, in accordance with certain embodiments."

For more information, see this patent application: Brown, Theresa M.; Francisco, Nedlaya Y.; Li, Suguang; Peterson, Beth A. Point in Time Copy Operations from Source Volumes to Space Efficient Target Volumes in Two Stages via a Non-Volatile Storage. Filed February 5, 2013 and posted August 14, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=507&p=11&f=G&l=50&d=PG01&S1=20140807.PD.&OS=PD/20140807&RS=PD/20140807

Keywords for this news article include: Information Technology, Information and Data Storage, International Business Machines Corporation.

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


For more stories covering the world of technology, please see HispanicBusiness' Tech Channel



Source: Information Technology Newsweekly


Story Tools






HispanicBusiness.com Facebook Linkedin Twitter RSS Feed Email Alerts & Newsletters