@Nullable
  public String getStoragePolicyName(String familyName) {
    if (this.fs instanceof HFileSystem) {
      Path storeDir = getStoreDir(familyName);
      return ((HFileSystem) this.fs).getStoragePolicyName(storeDir);
    }

    return null;
  }
Get the storage policy of the directory of CF.
@param familyName The name of column family.
@return Storage policy name, or {@code null} if not using {@link HFileSystem} or exception
        thrown when trying to get policy
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionFileSystem.java