During perf/scale testing, we see OOM on ODL when a large number of neutron resources are created and deleted we see that ODL is killed due to OOM. Looking at the stdout when the JVM crashed due to OOM, we see:

Heap dump file created [3089813876 bytes in 19.232 secs]
Uncaught error from thread [opendaylight-cluster-data-shard-dispatcher-144] shutting down JVM since 'akka.jvm-exit-on-fatal-error' is enabled for ActorSystem[opendaylight-cluster-data]
java.lang.OutOfMemoryError: Java heap space
at com.google.common.collect.RegularImmutableMap.createEntryArray(RegularImmutableMap.java:148)
at com.google.common.collect.RegularImmutableMap.<init>(RegularImmutableMap.java:81)
at com.google.common.collect.ImmutableMap.copyOf(ImmutableMap.java:294)
at org.opendaylight.controller.cluster.datastore.persisted.FrontendHistoryMetadata.<init>(FrontendHistoryMetadata.java:40)
at org.opendaylight.controller.cluster.datastore.FrontendHistoryMetadataBuilder.build(FrontendHistoryMetadataBuilder.java:54)
at org.opendaylight.controller.cluster.datastore.FrontendClientMetadataBuilder$$Lambda$431/741495460.apply(Unknown Source)
at com.google.common.collect.Iterators$8.transform(Iterators.java:799)
at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:48)
at java.util.AbstractCollection.toArray(AbstractCollection.java:141)
at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:258)
at org.opendaylight.controller.cluster.datastore.persisted.FrontendClientMetadata.<init>(FrontendClientMetadata.java:38)
at org.opendaylight.controller.cluster.datastore.FrontendClientMetadataBuilder.build(FrontendClientMetadataBuilder.java:77)
at org.opendaylight.controller.cluster.datastore.FrontendMetadata$$Lambda$430/2026307982.apply(Unknown Source)
at com.google.common.collect.Iterators$8.transform(Iterators.java:799)
at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:48)
at java.util.AbstractCollection.toArray(AbstractCollection.java:141)
at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:258)
at org.opendaylight.controller.cluster.datastore.persisted.FrontendShardDataTreeSnapshotMetadata.<init>(FrontendShardDataTreeSnapshotMetadata.java:71)
at org.opendaylight.controller.cluster.datastore.FrontendMetadata.toSnapshot(FrontendMetadata.java:72)
at org.opendaylight.controller.cluster.datastore.FrontendMetadata.toSnapshot(FrontendMetadata.java:33)
at org.opendaylight.controller.cluster.datastore.ShardDataTree.takeStateSnapshot(ShardDataTree.java:216)
at org.opendaylight.controller.cluster.datastore.ShardSnapshotCohort.createSnapshot(ShardSnapshotCohort.java:68)
at org.opendaylight.controller.cluster.raft.RaftActorSnapshotMessageSupport.lambda$new$0(RaftActorSnapshotMessageSupport.java:52)
at org.opendaylight.controller.cluster.raft.RaftActorSnapshotMessageSupport$$Lambda$123/1533883683.accept(Unknown Source)
at org.opendaylight.controller.cluster.raft.SnapshotManager$Idle.capture(SnapshotManager.java:295)
at org.opendaylight.controller.cluster.raft.SnapshotManager$Idle.capture(SnapshotManager.java:307)
at org.opendaylight.controller.cluster.raft.SnapshotManager.capture(SnapshotManager.java:91)
at org.opendaylight.controller.cluster.raft.behaviors.Follower.lambda$handleAppendEntries$0(Follower.java:254)
at org.opendaylight.controller.cluster.raft.behaviors.Follower$$Lambda$127/742332312.apply(Unknown Source)
at org.opendaylight.controller.cluster.raft.ReplicatedLogImpl.lambda$appendAndPersist$0(ReplicatedLogImpl.java:111)
at org.opendaylight.controller.cluster.raft.ReplicatedLogImpl$$Lambda$128/559701765.apply(Unknown Source)
at akka.persistence.UntypedPersistentActor$$anonfun$persist$1.apply(PersistentActor.scala:206)