Specifying class transition attributes

The class transition attributes allow you to specify:

• When a data set is eligible to transition
• Which copy technique to use to move the data set
• What action to take when there is a serialization error

There are three defined class transition attributes that can be used to specify if and when data sets should transition:

• TIME SINCE CREATION indicates the YEARS, MONTHS and/or DAYS that must elapse relative to the date that a data set was created. If left blank (the default value), this indicates that no transitions should occur based on these criteria.
• TIME SINCE LAST USE indicates the YEARS, MONTHS and/or DAYS that must elapse relative to the date that a data set was last referenced or used. If left blank (the default value), this indicates that no transitions should occur based on these criteria.
• PERIODIC indicates a MONTHLY, QUARTERLY or YEARLY cycle for which a data set should transition. If left blank (the default value), this indicates that no transitions should occur based on these criteria.

TRANSITION COPY TECHNIQUE specifies whether a point in time copy technique should be used. The available parameters are:

• STANDARD (STD)
• FAST REPLICATION PREFERRED (FRP)
• FAST REPLICATION REQUIRED (FRR)
• PRESERVE MIRROR PREFERRED (PMP)
• PRESERVE MIRROR REQUIRED (PMR)
• FC XRCPRIMARY (FCX)

These parameters function as follows:

• STANDARD (STD) specifies that only standard I/O should be used to perform the data movement. This is the default.
• FAST REPLICATION PREFERRED (FRP) specifies that fast replication should be used when possible. If fast replication cannot be used, then it is acceptable to use standard I/O to perform the data movement.
• FAST REPLICATION REQUIRED (FRR) specifies that fast replication is required. If fast replication cannot be used, then the transition fails.
• PRESERVE MIRROR PREFERRED (PMP) specifies that a Metro Mirror primary volume is allowed to become a FlashCopy® target, and it would be preferable that the Metro Mirror pair does not go into a duplex pending state as a result of the FlashCopy operation when the target volume is a Metro Mirror primary volume. If the preserve mirror operation cannot be accomplished, then the FlashCopy operation is still to be attempted. If the intended FlashCopy target volume is not a Metro Mirror primary volume, then the rules for FAST REPLICATION PREFERRED (FRP) are followed.
• PRESERVE MIRROR REQUIRED (PMR) specifies that a Metro Mirror or Global Mirror primary volume is allowed to become FlashCopy target volumes. If the FlashCopy target volume is a Metro Mirror primary device, a Preserve Mirror option is required when performing FlashCopy operation. If the target volume is not a Metro Mirror or Global Mirror primary volume, then the rules for FAST REPLICATION REQUIRED (FRR) are followed.
• FC XRCPRIMARY (FCX) specifies that an XRC primary volume is allowed to become a FlashCopy target. When the FCX option is set, the PMR option is also specified to DFSMSdss.

SERIALIZATION ERROR EXIT specifies an action to take when the data set cannot be exclusively serialized for the data movement. The available parameters are:

• NONE
• DB2®
• CICS®
• ZFS
• EXIT

These parameters function as follows:

• NONE specifies that the transition should fail with no additional action. This is the default.
• Db2 specifies that Db2 should be invoked to close the data set. If there are no Db2 transactions in progress and the data set is successfully closed and unallocated, then the data set will be exclusively serialized. If exclusive access is obtained, then the data set will be transitioned. After the data set has moved, Db2 is reinvoked to allocate and open the data set. If the serialization cannot be obtained or there are active Db2 transactions then the transition will fail.
• CICS specifies that CICS should be invoked to make the data set unavailable for use by CICS and to close all files open to the data set. If these steps are successful, then the data set will be exclusively serialized and then transitioned. After the data set has moved, CICS is reinvoked to enable the CICS files to use the data set and make available the data set to be used by CICS. If the serialization cannot be obtained a second time, then the transition will fail.
• ZFS specifies that zFS should be invoked to unmount the data set. If the data set is successfully unmounted, then the data set will be exclusively serialized. The unmount will fail if the file system is currently accessing the data set. If exclusive access is obtained, then the data set will be transitioned. After the data set has moved, zFS is reinvoked to mount the data set.
• EXIT specifies that a user exit should be invoked to unserialize the data set. The exit will be invoked twice: initially to unserialize the data set, and a second time after the transition in order to reserialize the data set. The transition will be performed if the data set can be exclusively serialized after the user exit has been initially invoked.