private WALProvider createProvider(String group) throws IOException {
    WALProvider provider = WALFactory.createProvider(providerClass);
    provider.init(factory, conf,
      META_WAL_PROVIDER_ID.equals(providerId) ? META_WAL_PROVIDER_ID : group, this.abortable);
    provider.addWALActionsListener(new MetricsWAL());
    return provider;
  }
A group-provider mapping, make sure one-one rather than many-one mapping
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/RegionGroupingProvider.java