private static long getLowestTimeStampFromFS(FileSystem fs,
    final Collection<HStoreFile> candidates) throws IOException {
    long minTs = Long.MAX_VALUE;
    if (candidates.isEmpty()) {
      return minTs;
    }
    Path[] p = new Path[candidates.size()];
    int i = 0;
    for (HStoreFile sf : candidates) {
      p[i] = sf.getPath();
      ++i;
    }

    FileStatus[] stats = fs.listStatus(p);
    if (stats == null || stats.length == 0) {
      return minTs;
    }
    for (FileStatus s : stats) {
      minTs = Math.min(minTs, s.getModificationTime());
    }
    return minTs;
  }
@param minVersions the MIN_VERSIONS for the column family
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestHStore.java