public static Path getRegionArchiveDir(Path rootDir, TableName tableName, Path regiondir) {
    // get the archive directory for a table
    Path archiveDir = getTableArchivePath(rootDir, tableName);

    // then add on the region path under the archive
    String encodedRegionName = regiondir.getName();
    return HRegion.getRegionDir(archiveDir, encodedRegionName);
  }
Get the archive directory for a given region under the specified table
@param tableName the table name. Cannot be null.
@param regiondir the path to the region directory. 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