Recovery Options
- Last UpdatedOct 04, 2024
- 2 minute read
- PI System
- PI Server 2023
- PI Server
Use this option to indicate whether the PIUnitBatches, PIBatches, and/or PISubBatches are recovered for each PIUnit in case the interface is shut down and restarted.
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The default option Recover all PIBatch objects recovers PIBatches, PIUnitBatches, and PISubBatches on the selected PIUnit.
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The Recover only PIBatches and PIUnitBatches option recovers only the PIBatches and PIUnitBatches on the selected PIUnit. The PISubBatches are not recovered.
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The Do not recover anything option will not recover any PIUnitBatches and PISubBatches on the selected PIUnit. During recovery, if there is a running PIUnitBatch, the recovery starts from the start time of that running PIUnitBatch irrespective of the Recovery Time specified. If there is no running PIUnitBatch, the interface searches for PIUnitBatches on the PIUnit up to Recovery Time into the past. If the search finds PIUnitBatches within that period, recovery is done from the end time of the last PIUnitBatch. If there are no PIUnitBatches in the search results, then recovery is done for Recovery Time into the past. This option helps in reducing the time it takes to recover if the recovery for that PIUnit is deemed not important.
Note: If PISubBatches are recovered, the PISubBatches on the running PIUnitBatch are removed and recreated based on the archive events. Since the interface depends on snapshot events during real-time operation and looks at archive events during recovery, it is possible that some of the SubBatches that are generated during real-time operation might be missing after recovery. This condition occurs only under certain circumstances. If there is a running PIUnitBatch at the time of recovery and if that PIUnitBatch has PISubBatches (running or not), those PISubBatchesare removed during recovery. If the start events for those SubBatches were not archived, then those PISubBatches will be missing after recovery. This occurs only for that one PIUnitBatch. This situation can be avoided by setting the compression parameters on the Active Point for the SubBatches such that all the start and stop events for the PISubBatches are archived.