When Couchbase Server is re-started, or when it is started after a restore from backup, the server goes through a warm-up process. The warm-up loads data from disk into RAM, making the data available to clients.

The warmup process must complete before clients can be serviced. Depending on the size and configuration of your system, and the amount of data that you have stored, the warmup may take some time to load all of the stored data into memory.