Data storage information

[natanael_mendes]

Where in documentation can I find the purpose of the Cassandra, nginx and Elasticsearch in Dynatrace Managed cluster?

[Julius_Loman]

Dynatrace Managed has to be considered as a packaged solution with several components.

Cassandra stores configuration data and metrics. Elasticsearch stores RUM data and log files for Log Monitoring v2 (logs classic). NGINX servers as load balancer and routes communication to particular endpoints and between cluster nodes.

[natanael_mendes]

thanks for the answer but where in documentation i can find the purpose of cassandra and elastic?

[Julius_Loman · Accepted solution]

@natanael_mendes in my previous post - it's a boxed solution, so you should not care about what data is stored in which technology as it may change between versions. Also you should not make any changes in the Cassandra or Elastic setting on the Managed node unless instructed to do so from the Dynatrace support.

About the data - I don't think this is documented in the public docs, but you can find relevant data in this post. 

[uros_djukic1]

Hello,
About Cassandra you will find here : Cassandra monitoring | Dynatrace Docs
About ElasticSearch  : Elasticsearch monitoring | Dynatrace Docs

Please be aware on the following fact : 
There are no sync transaction store so this means ElasticSearch and Cassandra sync between nodes which can also have an overall impact on storage as well; Thus the suggestion would be to spread this out and give each node its own storage type (a mount for cassandra, a mount for ElasticSearch and a mount for transaction storage for instance) as a minimum recommendation.

 For example, where Elastic storage and Cassandra all storages are on the same disk then reserved disk space is calculated as the sum of minimum required free disk space required by the respective data contributors (plus a 10% safety margin).
The individual calculation is done as:
For Cassandra reserved disk space: Current Cassandra usage * 0.6 (enough space for cassandra to do reorganization). Consequently take care during the backup operation due to disk compaction. 
interesting post : Solved: Re: Backup Size Ratio Cassandra vs. Elasticsearch - Dynatrace Community

More info hardware requirements : 
Managed hardware requirements | Dynatrace Docs

I hope that answered

[Malaik]

Hello All,

Do you have the info of how exactly the sync and the contribution of each nodes,

Lets assume that we have a set up with 6 nodes...

How the data is balanced and distributed, and what Dynatrace mange in case we have , 1, 2, or 3 nodes lost.

[radek_jasinski]

Dynatrace Managed uses a balanced distribution of data across the cluster. Data is replicated and distributed to ensure high availability and fault tolerance. If nodes are lost, Dynatrace automatically adapts to the new configuration, maintaining system operation and data access. However, some historical data (especially trace) may be lost. The number of nodes that can be lost without affecting operation depends on the cluster configuration and data replication settings.

Radek