[ONOS-7068] Upgrade to Atomix 2.0.4

Change-Id: I864567084b1ac230254533026f06d4a25e5e0a2d
diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/StoragePartitionServer.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/StoragePartitionServer.java
index 3a15fce..dbe712d 100644
--- a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/StoragePartitionServer.java
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/StoragePartitionServer.java
@@ -45,7 +45,7 @@
 
     private static final int MAX_SEGMENT_SIZE = 1024 * 1024 * 64;
     private static final long ELECTION_TIMEOUT_MILLIS = 2500;
-    private static final long HEARTBEAT_INTERVAL_MILLIS = 1000;
+    private static final long HEARTBEAT_INTERVAL_MILLIS = 250;
 
     private final MemberId localMemberId;
     private final StoragePartition partition;