Data Storage, is a module responsible for storing crawled items. On the high level it's possible to represent the architecture of items storage this way:

           ┌──────────────────┐
           │                  │             ┌------------------┐
           │   DataStorage    <─────────────┤ From crawlers1,2 │
           │                  │             └------------------┘
           └─────────┬────────┘
                     │
                     │
                     │
                     │
        ┌────────────▼─────────────────┐
        │                              │
        │                              │
        │                              │

┌───────────▼──────────┐ ┌───────────▼──────────┐ │ DataStorageWorker1 │ │ DataStorageWorker2 │ │ (Crawler1) │ │ (Crawler2) │ └──────────────────────┘ └──────────────────────┘