Elasticsearch actually sacrifices both consistency and availability during partitions, even when inside a single datacenter (trust me, they happen in production).
If you configure ES to prioritize consistency somewhat (minimum_master_nodes), it prevents writes during a partition—but there's at least one "split" partition scenario where even minimum_master_nodes doesn't prevent inconsistent writes. If you configure ES to prioritize availability during a partition, it isn't consistent. Remember, ES doesn't claim to be consistent and doesn't even use any sort of consensus algorithm.
If you configure ES to prioritize consistency somewhat (minimum_master_nodes), it prevents writes during a partition—but there's at least one "split" partition scenario where even minimum_master_nodes doesn't prevent inconsistent writes. If you configure ES to prioritize availability during a partition, it isn't consistent. Remember, ES doesn't claim to be consistent and doesn't even use any sort of consensus algorithm.