Additional information: IBM CICS VSAM Copy for z/OS V1.1IBM United States Software Announcement 205-191
August 16, 2005
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This announcement supplements and clarifies the information in Software Announcement 204-120 , dated June 8, 2004. It contains complete Description and Product positioning sections, which have been revised. The original announcement remains the source for other material, including ordering information.
CICS® VSAM Copy for z/OS® V1.1 (CICS VSAM Copy) is designed for creating copies of VSAM data sets that are used by CICS applications. This utility allows the creation of consistent copies of VSAM files with no impact to business-critical online processing. Copies are made without interrupting the online user, who can continue to update the VSAM data sets being copied. The online CICS user is completely unaware that the copy takes place there is no discernible effect on transaction response time in typical user situations.
Uniquely, CICS VSAM Copy creates a copy of a VSAM file, with full data integrity and consistency, without requiring activity on the VSAM data set to cease before starting the copy. The resulting copy does not contain any incomplete units of work (UOWs) and therefore does not require any further processing before it can be used.
Although designed to produce online copies of CICS files, the utility can also produce offline copies, without interaction with CICS.
Clarifications: CICS VSAM Copy can be compared to the IDCAMS REPRO facility in z/OS. CICS VSAM Copy functions as an online form of IDCAMS REPRO. It performs a logical record by record copy, and the format of the resultant output is identical to that produced by REPRO. However, CICS VSAM Copy allows these copies to be taken while the data sets remain available for update by CICS.
A copy generated by CICS VSAM Copy is defined as being consistent because it contains no incomplete UOWs. That is, if one update for a given UOW is reflected in the copy, then all updates for that UOW will be reflected.
Consistency would also result from any batch or offline "point-in-time" copy (as can be done by CICS
VSAM Copy running in batch mode). However, as CICS VSAM Copy when used online produces a
non-disruptive copy, it cannot have the "point-in-time" attribute.
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- CICS Transaction Server (CICS TS) for OS/390® V1.3 (5655-147)
- CICS TS for z/OS V2.2 or V2.3 (5697-E93)
- CICS TS for z/OS V3.1 (5655-M15)
For ordering, contact:
Your IBM representative or IBM Americas Call Centers at
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CICS VSAM Copy for z/OS V1.1 is a utility that allows you to create copies of one or more VSAM data sets. You can create copies of data sets that are allocated and open to CICS for update.
CICS is the foundation for running and managing many of the world's mainframe applications. VSAM manages more than 50% of corporate data worldwide. Although often taken for granted, CICS and VSAM are critical to many business applications. CICS provides the link between end users, their applications, and data stored in VSAM data sets.
CICS is also a fundamental part of today's on demand environment, often providing the primary transactional gateway for Internet or Intranet access to S/390® applications. Often it is new Web access to business applications that drives today's client needs for increased availability of online systems.
When a copy of critical VSAM data is required, for example for gathering an accurate snapshot of business information for offline analysis, users usually have to make a choice. They either keep the application available and have an inconsistent copy, or make the application unavailable while a consistent copy is made offline. Now, with the unique capabilities of CICS VSAM Copy, users can produce consistent copies online while keeping the application available to end users.
Online vs. offline copy
CICS VSAM Copy for z/OS V1.1 supports two modes of copying data sets: online mode and offline mode. Online mode means that the data set is open for update in a CICS region and can be updated during the copy process. Offline mode means the copy utility will attempt to allocate and open the data set according to the parameters specified. If successful, the copy will be made. Regardless of the copy mode, the resulting output format is similar to that produced by IDCAMS REPRO.
Online mode copy requests
The most important feature of CICS VSAM Copy for z/OS V1.1 is its ability to produce a consistent copy of a VSAM data set while it is being updated through CICS transactions. The online CICS user who may be concurrently updating the data set being copied does not have any indication that the copy is taking place. Of equal importance is the fact that the resulting copies do not contain any incomplete UOWs.
Offline copy requests are processed within both the copy utility's address space and the CICS region. In general, data is read from the data set from within the CICS region's address space. Data is subsequently written to the output data set by subtasks running within the copy utility's address space.
Offline mode copy requests
CICS VSAM Copy for z/OS V1.1 also supports offline copy requests. These are processed entirely in the copy utility's address space. There is no interaction with CICS. In general offline copy request processing is similar to IDCAMS REPRO processing. If a consistent, point-in-time copy is required for an offline copy, you must make sure the data set cannot be updated while the offline copy is in progress.
Dynamic mode copy requests
Dynamic mode allows the user to copy a data set without knowing whether a CICS region currently has update access to it. When a dynamic mode request is received, CICS VSAM Copy for z/OS V1.1 will first try to satisfy the request as an online mode copy by attempting to locate the data set within a CICS region. If a region that owns the data set cannot be found, CICS VSAM Copy for z/OS V1.1 will perform an offline copy for the data set.
Types of VSAM data sets supported
CICS VSAM Copy is capable of creating consistent copies for the following VSAM data sets that are under the control of a CICS region: Key Sequenced Data Set (KSDS), and Relative Record Data Set (RRDS) (refer to the restrictions listed at the end of this section).
Achieving consistent copies
A copy request is initiated through a standard MVS job step. After performing various initialization tasks it initiates a monitor task in the CICS region that owns the file. The monitor task runs as a standard CICS application task.
At this point, the request enters what is referred to as "Synchronization Phase" or "Phase 1". During Phase 1, "before-images" are kept for all updates to the file from tasks that started after the start of Phase 1. Phase 2 begins when all tasks that were active in the system before Phase 1 have either completed, or issued a syncpoint to start a new UOW, or been backed out.
During Phase 2, as the VSAM file to be copied is read sequentially, CICS VSAM Copy analyzes the before-image information alongside the records being read from the file to determine which records should appear in the output data set.
As a result, the consistent copy reflects only update activity that either happened before Phase 1 began or was part of a task or Unit of Work that was in progress when Phase 1 started. All activity from tasks started after the start of Phase 1 is completely excluded from the output data set.
The ability to create consistent copies online allows users of CICS VSAM Copy to avoid scheduling application downtime that may affect all end users. The user also gets the copy on demand rather than waiting for it to be scheduled.
While its online operation makes CICS VSAM Copy much more efficient than a traditional batch copy process, its ability to create consistent copies in real time offers substantial savings even over other copy utilities that claim to work "online". CICS VSAM Copy uniquely allows all applications and all users to remain online during the copy process, even when they require access to the file to be copied.
Because CICS VSAM Copy is easy to use and is non-disruptive, it can empower IT staff by eliminating the need to make copy requests through the data center, resulting in efficiency savings.
CICS VSAM Copy is compatible with SMP/E, DFSMSdss, System Managed Storage (SMS) and RACF®.
To simplify copy request processing, CICS VSAM Copy keeps an internal registry of all of the VSAM data sets owned by CICS regions that have CICS VSAM Copy started. By doing this, CICS VSAM Copy allows the user to copy or backup a data set without knowing which CICS region owns the data set.
Copy requests for multiple data sets
CICS VSAM Copy is capable of copying multiple VSAM data sets submitted in the same copy request. This can be useful, for instance, when copying all of the data sets that belong to the same application. The only restriction when doing this is that all of the data sets being copied in online mode must be owned by the same CICS region. If they are not, CICS VSAM Copy will detect this and the request will be terminated with an error. A request can consist of a mix of all of the supported data set types, subject to the restrictions listed at the end of this section.
Partial data set copy requests
CICS VSAM Copy allows the user to make partial copies of one or more VSAM data sets. This is accomplished by specifying a key range for the data set being addressed. Use of this feature will allow, for instance, users to create subsets of production data sets for uses such as testing.
CICS VSAM Copy uses the z/OS System Authorization Facility (SAF). Before beginning the process for a data set, CICS VSAM Copy will issue standard SAF calls to ensure the requestor has READ access to the data set being addressed. If not, the copy request will be terminated with an appropriate message.
Output Data Sets
CICS VSAM Copy can write output records to either:
Physical sequential data sets capable of being processed using standard QSAM methods. The data sets
can be blocked or unblocked, with fixed or variable record length.
VSAM data sets that match the input data sets in at least the following attributes:
- Type of VSAM data set (KSDS, RRDS or Entry Sequenced Data Set (ESDS))
- Maximum record length
- Key length and key position (if a KSDS)
Note: CICS VSAM Copy will not create the output data sets. They must be manually created and allocated to the copy job.
- Online copies of ESDS data sets are not supported.
- A copy produced by CICS VSAM Copy for an RRDS or VRRDS VSAM base cluster to a sequential data set will not preserve the original relative record number (RRN) of each record. Therefore, using the IDCAMS REPRO utility to restore the sequential copy back into a VSAM data set with similar physical attributes may cause the records to obtain an RRN that differs from that of the original data set at the time of the copy.
- Shareoption 3/4 data sets (or any other VSAM data sets that are capable of being updated from more than one CICS region) are not supported. If a request is received for a Shareoption 3/4 data set, CICS VSAM Copy will generate a job log message to this effect, then continue with the request. It is up to the user to ensure, before the process begins, that the data set is being updated only from the CICS region that CICS VSAM Copy is processing.
- ESDSs with alternate index paths are not supported, nor are they detected. It is the responsibility of the CICS VSAM Copy user to recognize this restriction and not to attempt to copy a data set in this scenario.
- VSAM KSDS data sets with alternate index paths cannot be copied through a path component. An attempt to do this will be detected and the request will be terminated. Copying a VSAM data set with alternate index path(s) through the base cluster is fully supported. CICS VSAM Copy also supports update activity through both the base and the paths while a copy through the base is in progress.
Accessibility by people with disabilities
CICS VSAM Copy for z/OS V1.1 is operated using the keyboard. The product displays standard 3270 panels, which are accessible by people with visual impairment by using assistive technology products. The product documentation is provided in softcopy (PDF) format, which is accessible.
Section 508 of the U.S. Rehabilitation Act
CICS VSAM Copy for z/OS V1.1 is capable as of June 25, 2004, when used in accordance with
IBM's associated documentation, of satisfying the applicable requirements of Section 508 of the
Rehabilitation Act, provided that any assistive technology used with the product properly
interoperates with it.
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CICS VSAM Copy V1.1 provides the ability to make consistent copies of VSAM datasets. It creates copies of VSAM datasets, with no interruption to online users, and typically no effect on transaction times while these copies are being made. CICS VSAM Copy manages the copying process, so that no incomplete units of work are included within the copy.
CICS VSAM Copy is a utility for producing ad-hoc copies for purposes such as reporting and testing, without affecting CICS activity. CICS VSAM Copy is not intended to be used as a production backup and restore product. The product's ability to create online copies that do not contain any incomplete units of work does not provide any functional advantage over existing IBM backup products in regards to recovery processing.
- Rapid copying of one or more VSAM files, with data consistency
- Can be used, by any authorized person, to make copies at any time
- Creates consistent copies of VSAM files, concurrent with business-critical online processing activity
- Resulting copies are similar in format to those that would be created by an IDCAMS REPRO
- Automatically registers all VSAM data sets in all participating CICS regions, so that a requester does not need to know which CICS region owns a data set to be copied
- Copying is not affected by control interval splits, control area splits, new extents, CICS task abends, or the backout of incomplete units of work
- Works with data sets that are distributed over multiple volumes, and are currently supported by CICS TS. Refer to restrictions in the Description section.
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