Why Is Memory Limited for Vultr Managed Databases for Caching?

Memory usage in Vultr Managed Databases for Caching (Valkey) is intentionally limited to ensure cluster stability and predictable performance. Several processes require reserved memory:

• Node Replication: When a new caching node connects to the existing master, the master forks a copy of itself and sends the current memory contents to the new node.
• Persistence to Disk: The database periodically persists its state to disk (typically every 10 minutes), which also involves forking a copy of the process.
• Copy-On-Write Behavior: When the database forks, all memory pages are initially shared between the parent and child processes, consuming no extra memory. However, any subsequent changes in the parent process cause the memory to diverge, increasing real memory usage.

Reserving memory helps prevent the database from over-consuming RAM, avoids system instability during replication or persistence operations, and ensures consistent performance across cluster nodes.