The Scylla team is pleased to announce the release of Scylla version 0.19.
Scylla is an open source, Apache-Cassandra-compatible NoSQL database, with superior performance and consistent low latency. This version is an incremental improvement release on the beta series, focused on stability and bug fixes. Noteworthy updates are:
- iotune is a new program which runs once as part of Scylla installation, analyzes the Scylla data drive, and extracts optimal values for the number of I/O queues and max I/O requests. The results are written to
/etc/scylla.d/io.conffor Scylla to use.
- Enable rolling upgrade with formal specification of internal protocols. Starting from release 0.19 and forward, all internal protocols, between nodes and to the disk, are defined by an IDL specification. This have two advantages:
- Make backward compatibility between Scylla version easier to define, implement and test. With the new specification, we can now guarantee internal communication will not be broken unintentionally by upgrades, allowing users to safely execute rolling upgrades of Scylla releases.
- Make it easier to create third-party tools to listen and interact with these protocols
- IO scheduler
Scylla support for system with slow disks was improved with the introduction of the new I/O scheduler. The new scheduler balances between I/O requests, including commitlog, flush and compaction, to make sure all get their fair share.
If I/O devices are too slow, it propagates the back pressure to the client, slowing down the request response rate to match the disk rate. In particular, this streamlines Scylla’s latency for slower disk cases, usually the case for some SSDs types in the public cloud and for HDDs.
A new CLI tool provide key scylla metrics on the terminal.
To also enable an external monitoring server, like collectd, graphite or similar, just update your local collectd server to act as a proxy.
A full list of contributions and known issues is available on the Scylla wiki.
Scylla is on track for a GA release in 2016 Q1. See the status page for complete feature and compatibility information.