MFE ConGroup: ConGroup tasks do not join the existing MODE MULTI ConGroup network
Summary: An existing MODE=MULTI Consistency Groups (ConGroup) network has four-member nodes on four Logical Partitions (LPARs). An additional two LPAR ConGroup tasks are configured to join the ConGroup network, however they instead create their own separate network. ...
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Symptoms
Two new ConGroup tasks were set up on two LPARs with the intention of joining the existing four-node ConGroup network.
No initial impact was noted as all ConGroup tasks continued to provide ConGroup protection. However, any commands entered on the OWNER LPAR are not propagated to the two new ConGroup tasks.
The existing four-member ConGroup network starts up. A four-node network is established.
When the two new ConGroup tasks are started using exactly the same initialization parameters, a separate two-node network is formed. Initially, the same OWNER LPAR is reported the same as the other four ConGroup tasks.
No initial impact was noted as all ConGroup tasks continued to provide ConGroup protection. However, any commands entered on the OWNER LPAR are not propagated to the two new ConGroup tasks.
The existing four-member ConGroup network starts up. A four-node network is established.
EMCP001I GLOBAL=(OWNER=MVSG) OWNER OF CONGROUP EMCP001I MODE=MULTI MULTI CONGROUP COMMUNICATION CGRP000I ConGroup V7.6 (10/03/13-11.20 SCGP760-SC76017) Initializing CGRP020I Established communications with SCF CGRP637I Initiating seek sequence CGRP751I MVSD CONNECTING CGRP752I MVSF PREVIOUSLY CONNECTED CGRP752I MVSG PREVIOUSLY CONNECTED CGRP752I MVSP PREVIOUSLY CONNECTED CGRP281I BUILD DATE: 10/03/13-11.20 SCGP760-SC76017 CGRP760I MULTI-NODE (4) NETWORK 0003082F ESTABLISHED
When the two new ConGroup tasks are started using exactly the same initialization parameters, a separate two-node network is formed. Initially, the same OWNER LPAR is reported the same as the other four ConGroup tasks.
EMCP001I GLOBAL=(OWNER=MVSG) OWNER OF CONGROUP EMCP001I MODE=MULTI MULTI CONGROUP COMMUNICATION CGRP000I ConGroup V7.6 (10/03/13-11.20 SCGP760-SC76017) Initializing CGRP020I Established communications with SCF CGRP637I Initiating seek sequence CGRP751I MVSE CONNECTING CGRP752I MVSB PREVIOUSLY CONNECTED CGRP760I MULTI-NODE (2) NETWORK 0001330C ESTABLISHED
Cause
All LPARs in this environment are on two separate physical processors. All LPARs run the same LOCAL TIME. The two LPARs that did not join the MULTI-NODE network have UTC time set to the Greenwich time. The other four LPARs have UTC time set to the local time. This is confirmed from the output of the 'D T' commands shown below.
CPU 2
CPU 1
MVSG - LOCAL: TIME=15.48.33 DATE=2014.153 UTC: TIME=15.48.33 DATE=2014.153 MVSD - LOCAL: TIME=15.48.37 DATE=2014.153 UTC: TIME=15.48.37 DATE=2014.153 MVSP - LOCAL: TIME=15.50.59 DATE=2014.153 UTC: TIME=15.50.59 DATE=2014.153 MVSE - LOCAL: TIME=15.48.27 DATE=2014.153 UTC: TIME=05.48.27 DATE=2014.153
CPU 2
MVSF - LOCAL: TIME=15.48.30 DATE=2014.153 UTC: TIME=15.48.30 DATE=2014.153 MVSB - LOCAL: TIME=15.48.24 DATE=2014.153 UTC: TIME=05.48.24 DATE=2014.153
Resolution
Workaround:
Previously the documentation stated the following:
To use MULTI-LPAR mode across LPARs and or sysplexes, the SYSTEM time must come from the same source. This could be the sysplex timer or a single Central Electronic Complex (CEC) clock.
Program Temporary Fixes (PTF) are developed which removes the requirement for using a common clock source for all LPARs in the MODE=MULTI network. With the PTF applied, UTC times may be different between the LPARs because timestamps between LPARs are normalized using CSC-provided real-time GMT differentials.
To use MULTI-LPAR mode across LPARs and or sysplexes, the SYSTEM time must come from the same source. This could be the sysplex timer or a single Central Electronic Complex (CEC) clock.
Program Temporary Fixes (PTF) are developed which removes the requirement for using a common clock source for all LPARs in the MODE=MULTI network. With the PTF applied, UTC times may be different between the LPARs because timestamps between LPARs are normalized using CSC-provided real-time GMT differentials.
Resolution:
- For Mainframe Enablers (MFE) 10.0.0, PTF SCA0032 has been developed to correct the issue and is available for download.
- For Mainframe Enablers 10.1.0, PTF SCA1014 has been developed to correct the issue and is available for download.
- For MFE 10.2.0, the issue is resolved in the base product. It is available to download.
All PTFs can be downloaded from Dell.com/Support.
Additional Information
For MFE 8.5, 10.0.0 or 10.1.0, without the above PTFs applied, the following note in the ConGroup Product Guide applies:
To use MULTI-LPAR mode across LPARs and or sysplexes, the LPAR time must come from the same source. This could be the sysplex timer or a single CEC clock.
To use MULTI-LPAR mode across LPARs and or sysplexes, the LPAR time must come from the same source. This could be the sysplex timer or a single CEC clock.
Affected Products
Mainframe EnablersArticle Properties
Article Number: 000055779
Article Type: Solution
Last Modified: 26 Jun 2025
Version: 6
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