With Couchbase Server 3.0, the new "full ejection" option allows for more efficient use of memory by caching larger parts of the working set, rather than just keys and metadata, which is particularly useful for large databases with a smaller active working set. This feature enables servers to reserve memory for 'hotter' parts of the data that are frequently accessed, reducing memory usage and improving performance. The new option can be easily enabled per bucket in the admin console, without requiring any changes on the application side. Benchmarks show significant reductions in memory consumption, with orders of magnitude less memory used for metadata compared to previous versions. However, this feature compromises on low-latency access to keys and metadata that have been ejected, requiring additional IO operations to retrieve them back into memory. This option is particularly suitable for large datasets and applications that don't require aggressive low latencies for all data access.