Method and system for incremental time zero backup copying of data

Abstract

Backup copying of designated datasets representing a first selected point in time consistency may be performed in a data processing system on an attached storage subsystem concurrent with data processing system application execution by first suspending application execution only long enough to form a logical-to-physical address concordance, and thereafter physically backing up the datasets on the storage subsystem on a scheduled or opportunistic basis. An indication of each update to a selected portion of the designated datasets which occurs after the first selected point in time is stored and application initiated updates to uncopied designated datasets are first buffered. Thereafter, sidefiles are made of the affected datasets, or portions thereof, the updates are then written through to the storage subsystem, and the sidefiles written to an alternate storage location in backup copy order, as controlled by the address concordance. At a subsequent point in time only those portions of the designated datasets which have been updated after the first selected period and time are copied, utilizing an identical technique.

Description

BACKGROUND OF THE INVENTION1. Technical Field:This invention relates in general to methods and systems for maintaining continued availability of datasets in external storage associated with accessing data processing systems, and in particular the present invention relates to backup copying of records in external storage concurrent with a dramatically shortened suspension of data processing system application execution occasioned by such copying. Still more particularly, the present invention relates to a method and system for incremental backup copying of records in a data processing system which minimizes still further the suspension of data processing system application execution during such copying.2. Description of the Related Art:A modern data processing system must be prepared to recover, not only from corruptions of stored data which occur as a result of noise bursts, software bugs, media defects, and write path errors, but also from global events, such as data processing sys...

AI Technical Summary

Benefits of technology

It is therefore one object of the present invention to provide an improved method and system for maintaining continued availability of datasets in external storage associated with accessing data processing systems.

It is another object of the present invention to provide an improved method and system for backup copying of records in external storage concurrent with a dramatically shortened suspension of data processing system application execution occasioned by such copying.

It is yet another object of the present invention to provide an improved method and system for incremental backup copying of records in a data processing system which minimizes, still further the suspension of data processing system application execution during such copying, as well as the actual amount of data which must be backed up.

Problems solved by technology

A modern data processing system must be prepared to recover, not only from corruptions of stored data which occur as a result of noise bursts, software bugs, media defects, and write path errors, but also from global events, such as data processing system power failure.

Thus, the opportunity cost of backing up data within a dataset may be quite high on a large multiprocessing, multiprogramming facility, relative to other types of processing.

However, this type of backup copying results in a consistency described as "fuzzy."

Requests and interrupts which occur prior to executing track-to-track customer data movement result in the restarting of the process.

This typically causes a requeueing of the request.

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