Scylla Open Source 3.0 is a landmark release for ScyllaDB: Materialized Views and Secondary Indexes are production-ready, and Scylla Open Source 3.0 can now read and write the Cassandra 3.x SSTable (“mc”) format. In addition, Scylla Open Source 3.0 provides a variety of performance improvements to existing functionality. In this article we will explore the nature of a pair of those performance improvements, and the scenarios in which Scylla users can expect to see a significant performance gain. Streaming When one Scylla node needs to transfer data to another, it undertakes a process called streaming. This happens when a new […]
This article will shed light on the performance penalties of running Scylla on Docker and discuss the tuning steps to solve them.
— When data is written to Scylla, one or more replicas may become unresponsive or unreachable. The reasons for that may range from a heavy load on a particular replica node, network congestion, hardware issues, etc. As a result, the write to a replica will fail, usually with the timeout error. To restore the consistency of the data across all replicas, a user will have to run a repair, which is a very expensive—and usually long—procedure.
A fast in-memory database provides benefits that we all can appreciate such as optimal latency and throughput for workloads. What if you could utilize extremely fast NVMe drives to have similar latency and throughput results? The scope of this blog post is to examine the outcomes of using an in-memory like database combined with NVMe drives to resolve cold-cache and data persistence challenges. In this experiment, various testing scenarios were done with Scylla and Intel® Optane™ SSD DC P4800X drives with a goal of providing a solution with the performance of an in-memory like database without compromises on throughput, latency, […]
In mid-2015, Intel and Micron jointly unveiled a new kind of non-volatile memory storage device named 3D XPoint (pronounced “cross-point”) that is 1000x faster than NAND. Now that 3D XPoint is generally available and has hit the broad market, we can start testing it. 3D XPoint uses electrical resistance and is considered to be bit addressable. It’s also worth mentioning that the endurance is much better with 3D XPoint because the stated wear leveling is 30 full drive writes per day for 5 years. 3D XPoint developers indicate that it is based on changes in resistance of the bulk material. […]
What’s the problem? Recently several NoSQL database clusters were targeted by hacker attacks. According to a report, the first known occurrences affected MongoDB, but soon after ElasticSearch clusters, Hadoop servers and CouchDB databases were affected as well. Is it relevant for the security of ScyllaDB installations? Heck yeah! In order to prevent an attack on your Scylla installation, proper configuration is critical from the get go.
Motivation Many times in real life installations, one of the most important parameters of the system is the longest response time. Naturally, the shorter, the better. Therefore capturing the request that took a long time and understanding why it took it so long is a very critical and challenging task. Slow query tracing to the rescue!
Tracing is a ScyllaDB tool that is meant to help developers and administrators analyze internal data flows in a Scylla cluster. One example of such a flow is CQL request processing. Tracing works much as it does in Apache Cassandra, so Cassandra tracing advice that you find online should be helpful on Scylla, too.
Distributed systems are hard to test, which means that creating a solid set of tests for a distributed database is a substantial software project in itself. Software developer Kyle Kingsbury has invented a full-featured tool for testing distributed systems, called Jepsen. (It’s named after Carly Rae Jepsen.) Jepsen is a flexible tool that can be set up to test a variety of distributed systems, including Apache Cassandra. Jepsen and Cassandra have both made a lot of progress since the original set of tests. Joel Knighton, a developer working at DataStax, has updated and enhanced the Jepsen tests for Cassandra and […]