@Override
  public DiskStoreFactory setDiskDirs(File[] diskDirs) {
    checkIfDirectoriesExist(diskDirs);
    int[] diskSizes = new int[diskDirs.length];
    Arrays.fill(diskSizes, DEFAULT_DISK_DIR_SIZE);
    return setDiskDirsAndSizes(diskDirs, diskSizes);
  }
Checks if directories exist, if they don't then create those directories
geode-core/src/main/java/org/apache/geode/internal/cache/DiskStoreFactoryImpl.java