MFE zDP: VDG fails to restart. EIP0206E MAX_SNAPSETS EXCEEDED after DYNAMIC_CHANGE

Summary: After a DYNAMIC_CHANGE to MAX_SNAPSETS or CYCLE_TIME error, the message may be seen during restart of the Versioned Data Group (VDG).

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Symptoms

A VDG is defined using the following definition and creates 8 secure and 24 non-secure SNAPSETs.

MAX_SNAPSETS(32) and CYCLE_TIME=(60,0,SECURE,2,5)
Calculation -
CYCLE_TIME(mmmm,count,SECURE,ddd,skip)  
1440*ddd/((skip+1)*mmmm) – 1440*2/6*60 = 2880/360 = 8 Secure and 24 non secure snapsets.

 A dynamic change is done to the VDG and too many non-secure SNAPSETs are in the VDG.

EIP0206E MAX_SNAPSETS EXCEEDED
VDG DYNAMIC_CHANGE(YES) allows a change while the VDG is active 
changing CYCLE_TIME=(60,0,SECURE,4,5)  
New calculation - 1440*4/6*60 = 5760/360 = 16 Secure. 
16 Secure minus 32 MAX is 16 Non Secure.
The VDG has 16 secure and 24 existing non-secure SNAPSETs 
Not the expected 16 Secure and 16 non-Secure SNAPSETS.

Eight of the non-SECURE SNAPSETs are terminated to reduce the count to 16 and the VDG starts successfully. 

NOTE: If a STOP is not issued after the dynamic change, the VDG runs with the 16 SECURE and 24 non-SECURE SNAPSETs. The MAX_SNAPSETs parameter of 32 is ignored. The VDG fails when a START is issued. 

 

Cause

Both Mainframe Enablers software for non-secure SNAPSETS termination and the POWERMAX/VMAX microcode for SECURE SNAPSETS recycles one SNAPSET at a time for each cycle. Any additional SNAPSETs above the calculation for secure and non-secure has to be verified and SNAPSETS terminated before the dynamic change. 

Resolution

Workaround:
 

Use the calculation to determine the number of secure snapsets. 
1440*ddd/((skip+1)*mmmm)
Take this number and subtract the number from MAX_SNAPSETS to determine the number of non-SECURE SNAPSETS. Ensure both the SECURE and non-SECURE SNAPSETS are less than these numbers. Terminate all SNAPSETS exceeding the numbers. 

A second option is to define a second VDG with the same devices if the SECURE SNAPSETS cannot be terminated to lower the number. The VMAX needs the Storage Resource Pool (SRP) space to accommodate this new VDG until the first VDG SECURE SNAPSETS expire and can be terminated. 
Depending upon the model and microcode level, older VMAX models only support 256 SNAPSETs. Microcode levels 5978.479.479 running on V3s and above supports 1024 MAX_SNAPSETS per device.

Remember that both the SECURE and non-SECURE SNAPSETs must be at or below the new calculation. The best practice would be to start small and work up adding more SECURE or non-SECURE SNAPSETs. The Storage Resource Pool (SRP) space is monitored along the way to ensure that space is available for production workloads. 


Permanent Fix:

  • For Mainframe Enablers 10.0.0, (Program Temporary Fix (PTF) SFA0058 and SNA0038 have been developed to correct the issue. It is available to download from Dell Online Support.
  • For Mainframe Enablers 10.1.0, Base software includes the fixes developed to correct the issue. It is available to download from Dell Online Support.

The URL to download the maintenance - Dell Online Support

Additional Information

Program Temporary Fix (PTF) description - 

++PTF(SFA0058) REWORK(2024004) .                                
++VER(Z038) FMID(SSCFA00)                                       
      PRE(                                                      
          SFA0030 SFA0057                                       
          ) .                                                   
++IF FMID(SSNPA00)                                              
      REQ(                                                      
          SNA0038                                               
          )                                                     
   /*                                                           
*-------------------------------------------------------------  
* PROBLEM DESCRIPTION(S):                                       
* ------------------------------------------------------------  
* PROBLEM FIXED: MFE-16008                                      
* USERS AFFECTED: zDP users                                     
* PROBLEM DESCRIPTION: Max_snapset value not honored.           
* DESCRIPTION DETAIL:                                           
*                                                               
* After a dynamic change, a running VDG no longer honors its    
* MAX_SNAPSET value.                                            
*                                                               
* PROBLEM RESOLUTION:                                           
*                                                               
* After a dynamic change, zDP now runs a validation routine to  
* ensure the devices in the VDG have snapset counts which       
* can support the MAX_SNAPSET value.                            
*                                                               
* * Note: This PTF requires MFE 10.0 PTF SNA0038 (corequisite)  
*

Affected Products

Mainframe Enablers
Article Properties
Article Number: 000197478
Article Type: Solution
Last Modified: 26 Jun 2025
Version:  3
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