Nutanix AES: Performance By Example PT2

How to improve large DB read performance by 2X

Nutanix AOS 5.10 ships with a feature called Autonomous Extent Store (AES).  AES effectively provides Metadata Locality to complement the existing data locality that has always existed.  For large datasets (e.g. a 10TB database with 20% hot data) we observe a 2X improvement in throughput for random access across the 2TB hot dataset.

In our experiment we deliberately size the active working-set to NOT fit into the metadata cache.   We uniformly access 2TB with a 100% random access pattern and record the time to access all 2TB.  On the same hardware with AES enabled – the time is cut in half.  As can be seen in the chart – the throughput is double, as expected.

It is the localization of metadata from AES that contributes to the 2X improvement.  AES keeps most of the metadata local to the node – so there is no need to fetch data across-the-wire.  Additionally  AES reduces the need to cache metadata in DRAM since local access is so fast. For very large datasets, retrieving metadata can contribute a large proportion of the access time.  This is true for all storage, so speeding up metadata resolution can make a dramatic improvement to overall throughput as we demonstrate.

Author: gary

Performance hacker @ nutanix.com