* Fault Tolerant - Data is automatically replicated to multiple nodes for fault-tolerance. Replication across multiple data centers is supported. Failed nodes can be replaced with no downtime. * Performant - Cassandra consistently outperforms popular NoSQL alternatives in benchmarks and real applications, primarily because of fundamental architectural choices. * Decentralized - There are no single points of failure. There are no network bottlenecks. Every node in the cluster is identical. * Durable - Cassandra is suitable for applications that can't afford to lose data, even when an entire data center goes down. * You're in Control - Choose between synchronous or asynchronous replication for each update. Highly available asynchronous operations are optimized with features like Hinted Handoff and Read Repair. * Elastic - Read and write throughput both increase linearly as new machines are added, with no downtime or interruption to applications. * Proven - Cassandra is in use at Constant Contact, CERN, Comcast, eBay, GitHub, GoDaddy, Hulu, Instagram, Intuit, Netflix, Reddit, The Weather Channel, and over 1500 more companies that have large, active data sets.

* The Scylla row cache, unlike the original Cassandra cache, is designed to reconcile data in cache with incoming writes. Cassandra’s row cache invalidates the whole partition for a given table on write, but Scylla’s does not. The result is that Scylla can run mixed read/write workloads efficiently. This reduces the need for data model complexity that is only present in order to work around the Cassandra read-before-write problem. Reducing data model complexity can have the indirect result of saving storage bandwidth as well. * Scylla does not need to parse cached data from stable format to in-memory format before serving it, because the Scylla row cache already holds data in the needed format. * Scylla is a new approach to NoSQL data store design, optimized for modern hardware. The typical design of NoSQL data stores (left) consists of a JVM which runs on top of Linux, utilizes the page cache, and uses complex memory allocation strategies to “trick” the JVM garbage collector to avoid stop-the-world pauses. Such a design suffers from sudden latency hiccups, expensive locking, and low throughput due to low processor utilization. * ScyllaDB networking is designed to squeeze the most out of the hardware. No different from the other Scylla components, we optimize the hell out our CPU, our memory management and similarly, the network. Scylla supports two different networking modes—our own native Seastar network stack and the traditional Linux stack.