The big news here is the recently released preview of HDInsight IO Cache, which is a new transparent data caching feature that provides customers with up to 9X performance improvement for Spark jobs, without an increase in costs.
There are many open source caching products that exist in the ecosystem: Alluxio, Ignite, and RubiX to name a few big ones. The IO Cache is also based on RubiX and what differentiates RubiX from other comparable caching products is its approach of using SSD and eliminating the need for explicit memory management. While other comparable caching products leverage the reservation of operating memory for caching the data.
Read on for more details.