ScyllaDB is designed to use all the memory it has and to put it to good use. Most notably to cache data. By default, when ScyllaDB starts up, it inspects the node’s hardware configuration and claims all memory to itself, leaving some reserve for the operating system. The assumption is that ScyllaDB does not run in a shared environment.
If for some reason you do want to give scyllaDB less memory, say for testing or development, you can do so:
- On Ubuntu, open a terminal and edit /etc/default/scylla-server, and add --memory 2G to restrict ScyllaDB to 2 gigabytes of RAM.
- On Red Hat / CentOS, open a terminal and edit /etc/sysconfig/scylla-server, and add --memory 2G to restrict ScyllaDB to 2 gigabytes of RAM.
- If starting ScyllaDB from the command line, simply append --memory 2G to your command line.
Additional Resources:
- Log-structured Storage and Compaction Fundamentals lesson on ScyllaDB University
- Memory Management lesson on ScyllaDB University
- How the ScyllaDB Data Cache Works blog post
- In-Memory Tables explained
- Running ScyllaDB in a Shared Environment on ScyllaDB Docs