1.1. Analysis Cockpit Architecture
The ASGARD Analysis Cockpit uses an Elasticsearch database to store all event data. Each day worth of incoming events uses a single Elasticsearch index.
Normally, Elasticsearch is running locally on the Analysis Cockpit Server. However, when required Elasticsearch can easily be extended to become a cluster of almost arbitrary size.
When running in Cluster mode, the Analysis Cockpit runs the underlying metadata database and acts as the cluster master, while all data is stored on the additional nodes.
1.2. When to consider Clustering
You should consider extending the Elasticsearch installation to become a cluster if:
there is significant performance degradation
for searches that cover multiple days and/or
for adding events to cases.
performance cannot be sufficiently improved by adding more CPU cores or faster disks (RAM is supported up to 32GB)
disk size of the analysis cockpit cannot be increased but retention period requires additional storage
Benchmarks suggest there is a communication overhead of 10% - 20% for a cluster compared to a single node in cases where a single node would be sufficient for the given load.
As logs of one day are stored in one index and indices are distributed over cluster members the performance gain will also depend on the number of days stored in the cluster.
In a cluster configuration the former Analysis Cockpit will act a master and will hold no data. Therefore, the minimum reasonable cluster size is three. In such a minimum configuration we expect a performance gain of 60% given we have at least 60 days of logs.