RESET SMDS (reset shared message data sets) on z/OS

Use the MQSC command RESET SMDS to modify availability or status information relating to one or more shared message data sets associated with a specific application structure.

Using MQSC commands

For information on how you use MQSC commands, see Performing local administration tasks using MQSC commands.

Parameter descriptions for RESET SMDS

This command is only supported when the CFSTRUCT definition is currently using the option OFFLOAD(SMDS).

SMDS(qmgr-name|*)

Specify the queue manager for which the shared message data set availability or status information is to be modified, or an asterisk to modify the information for all data sets associated with the specified CFSTRUCT.

CFSTRUCT( structure-name )

Specify the coupling facility application structure for which the availability or status information for one or more shared message data sets is to be modified.

ACCESS( ENABLED|DISABLED )

This keyword is used to enable and disable access to a shared message data set, making it available or unavailable to the queue managers in the group.

This keyword is useful when a shared message data set is required to be temporarily unavailable, for example while moving it to a different volume. In this instance, the keyword would be used to mark the data set as ACCESS(DISABLED) causing all of the queue managers to close it normally and deallocate it. When the data set is ready to be used, it can be marked as ACCESS(ENABLED) allowing the queue managers to access it again.

ENABLED

Use the ENABLED parameter to enable access to the shared message data set after previously disabling access, or to retry access after an error has caused the availability state to be set to ACCESS(SUSPENDED).

DISABLED

Use the DISABLED parameter to indicate that the shared message data set cannot be used until the access has been changed back to ENABLED. Any queue managers currently connected to the shared message data set are disconnected from it.

STATUS(FAILED | RECOVERED)

This keyword is used to specify that a shared message data set requires recovery/repair, or to reset the STATUS of the data set from FAILED.

If you have detected that a data set is in need of repair, this keyword can be used to manually mark the data set as STATUS(FAILED). If the queue manager detects that the data set requires repair, it automatically marks it as STATUS(FAILED). Then if RECOVER CFSTRUCT is used to successfully complete a repair to the data set, the queue manager automatically marks it as STATUS(RECOVERED). If another method is used to successfully repair the data set, this keyword can be used to manually mark the data set as STATUS(RECOVERED). It is not necessary to manually alter the ACCESS, as it is automatically changed to SUSPENDED while the STATUS is FAILED and then back to ENABLED when the STATUS is set to RECOVERED.

FAILED

Use the FAILED parameter to indicate that the shared message data set needs to be recovered or repaired, and should not be used until this has been completed. This is only allowed if the current state is STATUS(ACTIVE) or STATUS(RECOVERED). If the current availability state is ACCESS(ENABLED) and is not changed on the same command, this sets ACCESS(SUSPENDED) to prevent further attempts to use the shared message data set until it has been repaired. Any queue managers currently connected to the shared message data set are forced to disconnect from it, by closing and deallocating the data set. This status may be set automatically if a permanent I/O error occurs when accessing a shared message data set or if a queue manager determines that header information in the data set is invalid or is inconsistent with the current state of the structure.

RECOVERED

Use the RECOVERED parameter to reset the state from STATUS(FAILED) if the shared message data set does not actually need to be recovered, for example if it was merely temporarily unavailable. If the current availability state (after any change specified on the same command) is ACCESS(SUSPENDED), this sets ACCESS(ENABLED) to allow the owning queue manager to open the shared message data set and perform restart processing, after which the status is changed to STATUS(ACTIVE) and other queue managers can use it again.