@Override
    public long getTotalDataSize(Map<PartitionedRegion, InternalPRInfo> details) {
      long totalSize = 0;
      if (details != null) {
        for (PartitionedRegion region : details.keySet()) {
          InternalPRInfo info = details.get(region);
          Set<PartitionMemberInfo> membersInfo = info.getPartitionMemberInfo();
          for (PartitionMemberInfo member : membersInfo) {
            if (logger.isDebugEnabled()) {
              logger.debug("Region:{}, Member: {}, Size: {}", region.getFullPath(), member,
                  member.getSize());
            }
            totalSize += member.getSize();
          }
        }
      }
      return totalSize;
    }
Hides cache level details and exposes simple methods relevant for auto-balancing
geode-rebalancer/src/main/java/org/apache/geode/cache/util/AutoBalancer.java