Alluxio provides a distributed data access layer for applications like Spark or Presto to access different underlying file system (or UFS) through a single API in a unified file system namespace. If users only interact with the files in the UFS through Alluxio, since Alluxio has knowledge of any changes the client makes to the UFS, it will keep Alluxio namespace in sync with the UFS namespace.
Software Engineer, Alluxio
This blog describes our experience in speeding up Alluxio metadata operations using fingerprint and Alluxio under store bulk operations. These latest optimizations can be found in the 1.8.1 release.
One of the major values Alluxio provides is a simple and unified interface to manage files and directories on different underlying storage systems. Alluxio acts as an intermediate layer and exposes a file interface for applications to interact with, even though the underlying storage system might be an object store that has a different interface.