IBM DB2 Cloning Tool: Deprecation of Tablespace / Application Cloning SRCVSCPY Data Mover
I know that’s a boring title, but I decided to just get to the point. Please read on to discover why this is a positive change.
The IBM Db2 Cloning Tool offers several methods to move data from the source to the target. Full descriptions are in the User’s Guide. A summary follows:
- ADRDSSU or EMCAPI for Flashcopy/TimeFinder offers fast replication or host-based copies of the Db2 linear VSAM datasets. ADRDSSU includes the option to clone from Flashcopy for consistent image copies.
- SRCIMCPY to use image copies as the source.
- SRCVSCPY for customers that may have Flashcopy restrictions and want to clone directly from the source without using image copies or fast replication. In this case, the Cloning Tool copies the source VSAM data sets directly.
- NONE can be used to verify cloning use cases prior to execution or when the user plans to move the data set outside of the tool.
These options can be seen on the COPY Command panel as shown below.
The SRCVSCPY option, which is known as VSAM-to-VSAM, has been deprecated. This means that the feature may not be improved in future maintenance and will be removed at some, yet to be determined, future date. Better options already exist within the Db2 Cloning Tool with fewer restrictions and the potential for better performance.
Why has this been done and what are your options?
The adoption of the SRCVSCPY feature has been low and our performance testing indicates that the Cloning Tool already has another option which should offer customers better performance today. ADRDSSU has extended options to control how it operates.
When ADRDSSU is selected as the DATA-MOVER PGM on the COPY Command panel, enter a panel command of “P” to see these options. The FASTREP option is set to PREF by default. This means that Flashcopy is preferred when it is available. PREF determination is at run time. In most cases, this is the desired option. However, for customers that cannot use Flashcopy, setting FASTREP to NONE will cause ADRDSSU to choose a host-based copy option. If you are an SRCVSCPY customer, please begin to investigate this existing alternative and make plans to move in this direction.
Notice that the ADRDSSU parameters panel also has FCTOPPRCPRIMARY (has been in V3.2 since GA) and FCTOXRCPRIMARY (PH21116) options. These may offer some assistance to customers that have been avoiding using Flashcopy when the target volume is also a Metro Mirror or Global Mirror primary volume using PPRC or XRC. Normally a PPRC or XRC primary volume cannot be the target of a Flashcopy relationship.
For Metro Mirror, FCTOPPRCPRIMARY allows the Flashcopy target volume to be in a PPRC volume relationship. When the Preserve Mirror feature of Enterprise Storage System is available, these options allow the Flashcopy operation to proceed and provide controls for managing the duplex pending status. See the Cloning Tool User’s Guide for more information, and see the DFSMSdss Storage Administration Reference for more information about the preserve mirror options.
For Global Mirror, FCTOXRCPRIMARY allows the Flashcopy target volume to be in an XRC volume relationship. To avoid disruption to the mirror or consistency at the remote site, Remote Pair Flashcopy for XRC should be available and configured. See the Cloning Tool User’s Guide for more information about invoking this parameter via a cloning operation. See the z/OS DFSMS Advanced Copy Services for setting up RPFC for XRC.
Either of these options may require READ access to the appropriate facility class, FCTOPPRCCP or FCTOXRCCP.
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