IonDB vs Scylla: What are the differences?
IonDB: A key-value store for microcontroller and IoT applications. Currently in the Arduino world, there doesn't exist an associative array or map implementation that is both easy to use and performance competitive. There also is little support for disk based storage options that don't involve writing it yourself. IonDB is fast, functional, and offers disk based storage out of the box; Scylla: Next Generation Cassandra. Real-time big data database, with scale-up performance of 1,000,000 IOPS per node, scale-out to 100s of nodes and 99 latency of less than 1 msec.
IonDB and Scylla belong to "Databases" category of the tech stack.
IonDB and Scylla are both open source tools. It seems that Scylla with 5.18K GitHub stars and 615 forks on GitHub has more adoption than IonDB with 526 GitHub stars and 37 GitHub forks.