Alert: Potential Integrity Issue with Mirroring

July 6th, 2016

InterSystems has corrected a defect with Mirroring that can impact data integrity

The defect is present in all released versions Caché, Ensemble, and HealthShare beginning with 2015.2.0. It is present for all platforms and affects both failover and asynchronous mirroring configurations.The nature of the defect is that updates may be skipped when journals are applied to a non-primary system. The defect is only triggered under certain unusual conditions when a non-primary mirror member is starting or reconnecting.

InterSystems recommends, in addition to obtaining the correction, that at-risk systems be checked for impact. There are two methods to do this:

1. A utility, available via FTP here, can be used to scan a series of cconsole.log files and determine that a system has not been impacted. To ensure a complete check the routine must scan all cconsole.log files generated since a system was upgraded to 2015.2+. Load it in any namespace and invoke it interactively with ‘do ^SML2330Alert’.
2. The ^DATACHECK utility can be used to check that destination and source systems are in sync.

If either check indicates a problem, please contact InterSystems Worldwide Response Center (WRC) for further assistance. The affected mirror member may need to be rebuilt; information on rebuilding a mirror member can be found here.

The correction for this defect is identified as SML2330. It will be included in all future product releases including the upcoming 2015.2.4 and 2016.1.2 maintenance distributions. It is also available via ad hoc distribution as a patched routine. If you have any questions regarding this alert, please contact InterSystems Worldwide Response Center.