/** @throws Exception If failed. */
  public void testCreateFileColocated() throws Exception {
    GridGgfsPath path = new GridGgfsPath("/colocated");

    UUID uuid = UUID.randomUUID();

    GridUuid affKey;

    long idx = 0;

    while (true) {
      affKey = new GridUuid(uuid, idx);

      if (grid(0).mapKeyToNode(DATA_CACHE_NAME, affKey).id().equals(grid(0).localNode().id()))
        break;

      idx++;
    }

    try (GridGgfsOutputStream out = fs.create(path, 1024, true, affKey, 0, 1024, null)) {
      // Write 5M, should be enough to test distribution.
      for (int i = 0; i < 15; i++) out.write(new byte[1024 * 1024]);
    }

    GridGgfsFile info = fs.info(path);

    Collection<GridGgfsBlockLocation> affNodes = fs.affinity(path, 0, info.length());

    assertEquals(1, affNodes.size());
    Collection<UUID> nodeIds = F.first(affNodes).nodeIds();

    assertEquals(1, nodeIds.size());
    assertEquals(grid(0).localNode().id(), F.first(nodeIds));
  }
  /** {@inheritDoc} */
  @Override
  public void isolated(boolean isolated) throws GridException {
    if (isolated()) return;

    GridNode node = F.first(ctx.grid().forCache(cacheName).nodes());

    if (node == null) throw new GridException("Failed to get node for cache: " + cacheName);

    GridCacheAttributes a = U.cacheAttributes(node, cacheName);

    assert a != null;

    updater =
        a.atomicityMode() == GridCacheAtomicityMode.ATOMIC
            ? GridDataLoadCacheUpdaters.<K, V>batched()
            : GridDataLoadCacheUpdaters.<K, V>groupLocked();
  }