Give it more resources. Bulkloader uses resources exponentially based on the dataset size, especially RAM. In general for small (21mi) bulk loads we set 20GB for safety. And way more for bigger datasets. I think the dev team has some improvements coming to the bulk loader. But not sure when it would be available.
When the bulk is finished, you can return the machine to your default resource config you were using.
This do nothing, LRU is a cache for queries. And it is disabled until we add Ristretto cache to Dgraph.