Fluentd vs syslog-ng

Fluentd is a free, open-source data collector for creating a unified logging layer. It uses JSON to handle log collection, filtering, buffering, and output across sources and destinations. More than 500 community plugins connect it to data sources and outputs, including Elasticsearch and Kibana, Splunk, AWS S3, Kafka, BigQuery, Datadog, and OpenTelemetry. It supports memory and file buffering, failover, and high availability to help prevent data loss between nodes. The project reports that a vanilla instance uses 30–40 MB of memory and can process 13,000 events per second per core. Fluentd v1 runs on Linux, Mac OSX, and Windows; community distributions also include Docker images, a Kubernetes DaemonSet, and Ruby gems. It is self-hosted, and its components are available under the Apache 2 License. The project lists community help and commercial support from companies offering enterprise services. The homepage notes vulnerabilities patched in Fluentd v1.19.3 and advises updating fluent-package to v6.0.4.

syslog-ng collects infrastructure logs, processes them, and routes or stores them for analysis. Its free Open Source Edition can collect, parse, classify, rewrite, and correlate logs before sending them to analysis tools or storing them. Premium Edition adds filtering and real-time pattern correlation to reduce and normalize log data, plus disk buffering, client-side failover, and application-layer acknowledgements. It supports TLS-encrypted transfer and encrypted log storage with X.509 certificates for mutual authentication. Store Box offers access-controlled search and custom reports that can help with compliance work. Listed destinations include Elasticsearch, Hadoop, Kafka, MongoDB, SQL databases, Redis, Splunk, and SIEM tools. Premium licensing is based on Log Source Hosts, with annual support available; Store Box licensing depends on Log Source Hosts and hardware configuration. Open Source Edition is GPL/LGPL licensed and community supported. Commercial customers can access certified engineers and support services; Premium Edition and Store Box offer free trials.