private void verify(Shard[] shards) throws IOException {
// verify the index
IndexReader[] readers = new IndexReader[shards.length];
for (int i = 0; i < shards.length; i++) {
Directory dir =
new FileSystemDirectory(fs, new Path(shards[i].getDirectory()),
false, conf);
readers[i] = IndexReader.open(dir);
}
IndexReader reader = new MultiReader(readers);