public static Path getRegionArchiveDir(Path rootDir, TableName tableName,
    String encodedRegionName) {
    // get the archive directory for a table
    Path archiveDir = getTableArchivePath(rootDir, tableName);
    return HRegion.getRegionDir(archiveDir, encodedRegionName);
  }
Get the archive directory for a given region under the specified table
@param rootDir   {@link Path} to the root directory where hbase files are stored (for building
                 the archive path)
@param tableName name of the table to archive. Cannot be null.
@return {@link Path} to the directory to archive the given region, or <tt>null</tt> if it
        should not be archived
hbase-server/src/main/java/org/apache/hadoop/hbase/util/HFileArchiveUtil.java