what is ferrodruid fr?

FerroDruid is a database written in Rust that aims to work the same way as Apache Druid, a system used for storing and querying large amounts of time-stamped data in real time. The project is not made by or connected to the Apache Software Foundation. It is an independent rebuild of the public Druid data formats and network protocols, written from scratch. The main selling point is simplicity of deployment. A standard Druid setup needs six separate Java processes plus a coordination service and a separate metadata database. FerroDruid can run the whole system as one single compiled binary, with its own built in coordination using a library called openraft, so there is no Java runtime and no external coordination service to install. It can also run as six separate binaries, one per role, for larger setups that want the pieces split apart. The project includes a compatibility checker called ferro-logcompat, which reads a log of past Druid queries and reports which ones FerroDruid can already handle, which are partially supported, and which are not supported at all. It runs locally, does not touch your live Druid cluster, and does not send your query data anywhere. Supported features include the common SQL clauses such as SELECT, WHERE, GROUP BY, HAVING, ORDER BY, LIMIT and OFFSET, along with several Druid specific SQL time and string functions. It also implements all eight of Druid's native query types in single binary mode, with four of them working end to end when running as six separate role binaries. When roles talk to each other over the network, encrypted and verified connections are required by default. FerroDruid ships prebuilt images and deployment tools through AWS Marketplace, including an AMI, a container image, a Helm chart and a Terraform module. The license is BUSL-1.1, which restricts some commercial use rather than being fully open license, and the project documents known limitations and version by version compatibility results openly in its docs folder.