Emc IP Holding Company LLC

Evan G Jones

Douglas Eric LeCrone

Brett A Quinn

Paul A Linstead

Ning Wu

Eugene D Pflueger

Amir Holtzman

Obtaining a consistent set of snapshots of a group of storage volumes includes obtaining a plurality of snapshots, each of the snapshots being for one of the volumes, determining if there are any specific write operations to at least one volume that occurred after obtaining a first one of the snapshots and before obtaining a last of the snapshots, if there are any specific write operations, discarding the plurality of snapshots, and, if there are no specific write operations, designating the plurality of snapshots as the consistent set of snapshots. Obtaining a consistent set of snapshots may include repeatedly obtaining a plurality of snapshots and determining if there are specific write operations until either a particular condition is met or there are no specific write operations determined. The particular condition may be exceeding a predetermined number of iterations or a predetermined time limit.

Snapshots with selective suspending of writes

Creating snapshot data sets for a plurality of logical devices of a storage system includes marking an initial set of the logical devices for a snapshot in response to each of the initial set of logical devices having been modified since obtaining a previous snapshot data set, suspending I/O operations, marking an additional set of the logical devices for a snapshot in response to each of the additional set of logical devices having been modified prior to suspending I/O, performing a snapshot of the logical devices in the initial set of logical devices and in the additional set of logical devices, and resuming I/O operations. Pointers to snapshots for the snapshot data set may be placed in a table that includes a plurality of entries for a plurality of snapshot data sets. None of the additional set of logical devices may be part of the initial set of logical devices.

Optimizing snapshot creation

Systems and techniques are provided for incremental Continuous Data Protection (iCDP) as a process to secure frequent, and space efficient, versions of consistent point-in-time images of a group of volumes using snapshot technology. The system provides for automation to create and manage frequent snapshots of defined groups of volumes. The incremental approach of the system described herein provides a convenient way to roll back to prior point-in-time versions to investigate data damage due to processing errors or other forms of corruption. Log space in log devices may be reclaimed in connection with managing recovery and roll back capabilities of the system to desired data versions for purposes of data protection. Point in time versions of a source device may be accessed through the source device. The particular point in time version accessed in servicing an I/O may be determined in accordance with one or more criteria.

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Glenville, NY, United States of America

Evan G Jones