Apache Pinot

```If there are multiple controllers, Pinot expects that all of them are configured with the same back-end storage system so that they have a common view of the segments (e.g. NFS). Pinot can use other storage systems such as HDFS or ADLS```
I can't find more info about this.  Would any mountable NFS work?  S3 for example?

Yes. NFS would work. So would any deep store 

We have implementations for NFS, ADLS, S3 and GCS

Correct. S3/ADL/GCS as deep-stores can be shared across controllers without any further need of NFS on top of that.

<https://docs.pinot.apache.org/users/tutorials/use-s3-as-deep-store-for-pinot|https://docs.pinot.apache.org/users/tutorials/use-s3-as-deep-store-for-pinot>