Observed SegmentNotFound Exceptions in the logs. For example:
*ERROR* [FelixStartLevel] org.apache.sling.event [org.apache.sling.event.impl.jobs.queues.QueueManager(1431)] The activate method has thrown an exception (org.apache.jackrabbit.oak.plugins.segment.SegmentNotFoundException: Segment da5bcb95-d00a-4c04-a9d9-0f10f2b14e5e not found)
*ERROR* [pool-6-thread-3] org.apache.sling.commons.scheduler.impl.QuartzScheduler Exception during job execution of org.apache.jackrabbit.oak.plugins.index.AsyncIndexUpdate@1dc173f9 : Segment e669f30b-e886-4b7a-b161-56432601ec6b not found
org.apache.jackrabbit.oak.plugins.segment.SegmentNotFoundException: Segment e669f30b-e886-4b7a-b161-56432601ec6b not found
Due to some older issues in Oak or some inconsistencies in the repository, a segment can go missing and repository might be inconsistent.
Run consistency check on the repository and find the last good revision [healthy state] and revert back to it. Please do the following:
Download a version of oak-run that matches your oak core version from https://mvnrepository.com/artifact/org.apache.jackrabbit/oak-run
For AEM 6.0 instances, please use a version of oak-run (oak-run-1.1.7.jar or above), which has the new check run-mode https://github.com/apache/jackrabbit-oak/blob/trunk/oak-run/README.md#check
This helps checking the segment node store inconsistencies.
Run the consistency check,
java -Xmx6000m -jar oak-run-*.jar check -d1 -p /path/to/crx-quickstart/repository/segmentstore
This searches backwards through the revisions until it finds a consistent one:
Look for message like below:
[main] INFO o.a.j.o.p.s.f.t.ConsistencyChecker - Found latest good revision afdb922d-ba53-4a1b-aa1b-1cb044b535cf:234880