IBM Support

Steps for backing up and fallback process with SMS CDS's when upgrading to a new z/OS level

How To


Summary

Here are steps to take when planning to upgrade to a new level of z/OS regarding the SMS ACDS/COMMDS so that fallback is possible

Steps

When planning to upgrade z/OS, it is important to ensure that all toleration and co-existence maintenance is installed to the lower-level systems. This maintenance ensures lower-level SMS systems can tolerate changes to control blocks in the SMS CDSs.  PSP bucket information provides this information.

Once you implement the higher-level system, all changes must be done from the highest level z/OS system so new features introduced at the higher-level system are tolerated throughout the SMSplex.  Failure to do so might result in various SMS issues when SMS is accessing the SCDS/ACDS.
It is always a good idea and best practice to issue a SETSMS SAVEACDS(bkup.acds) and SETSMS SAVESCDS(bkup.scds) commands anytime SMS changes are implemented. These commands allow the ability to back out the changes, if required.      
Backing up the SMS CDS data sets, does not require all sharing systems to be down.  The commands can be issued from any current system before you do the upgrade.          
These instructions assume no changes are made to the IGDSMSxx parmlib member.                
Steps to back up your environment before the z/OS upgrade:                                                    

----------------------------------------------------------------------

  1.  Allocate backup bkup.scds, bkup.acds and empty.commds data sets. Use the sample JCL provided in the manual.  Adjust the size of the data set based on what is allocated. Please refer to:   z/OS DFSMSdfp Storage Administration. Allocating control data sets
  2.  Issue SETSMS SAVESCDS(bkup.scds).         This command saves the current SCDS to a copy. If any changes are made in the SCDS,  they will not be saved to the backup copy.
  3.  Issue SETSMS SAVEACDS(bkup.acds).        This command saves the current ACDS to a copy.  If any changes are made in the ACDS, they will not be saved to the backup copy
  4. To create bkup.commds data set, issue SETSMS COMMDS(empty.commds). This will activate the empty COMMDS so the original COMMDS can be freed for rename to bkup.commds when backing out any changes.

If there is a need to fall back to lower level systems, use these next steps to back out to previous SMS control data sets:                                         

----------------------------------------------------------------------------------------------------------------------------------------                                        

  1.   Issue SETSMS COMMDS(bkup.commds). This reverts to the bkup.commds used after the upgrade.
  2.   Issue SETSMS ACDS(bkup.acds).   This command backs out the current ACDS. Any changes that were done on the higher-level ACDS are lost.  It is recommended that all changes to the SMS configurations be put on hold or documented so they can be re-implemented.                                                   
  3.   Rename the original COMMDS (specified in IGDSMSxx parmlib) to a new name.
  4.  Allocate a new empty COMMDS with the original name (specified in IGDSMSxx parmlib).
  5.  Rename the original ACDS (specified in IGDSMSxx parmlib) to a new name.
  6.  Allocate a new ACDS with the original name (specified in IGDSMSxx parmlib).
  7.  Issue SETSMS SAVEACDS(original.name.ACDS)  <---created in step 6
  8. Rename the original SCDS to a new name.                                                              
  9.  Allocate a new SCDS with the original name.                            
  10.  Issue SETSMS SAVESCDS(original.name.SCDS) <---created in step 9
  11.  Ensure IGDSMSxx parmlib member reflects the original ACDS and COMMDS data set names before SMS is restarted.
  12.  Issue SETSMS COMMDS(original.name.COMMDS)      - to get back to the original data set name
  13.  Issue SETSMS ACDS(original.name.ACDS)                   - to get back to the original data set name              

       
              
                                      

Document Location

Worldwide

[{"Line of Business":{"code":"LOB56","label":"Z HW"},"Business Unit":{"code":"BU070","label":"IBM Infrastructure"},"Product":{"code":"SWG90","label":"z\/OS"},"ARM Category":[],"Platform":[{"code":"PF035","label":"z\/OS"}],"Version":"All Version(s)"}]

Document Information

Modified date:
29 October 2024

UID

ibm16377940

Page Feedback