Anytime you restart the Couchbase Server, or when you restore data to a server instance, the server must undergo a warmup process before it can handle requests for the data. During warmup the server loads data from disk into RAM; after the warmup process completes, the data is available for clients to read and write. Depending on the size and configuration of your system and the amount of data persisted in your system, server warmup may take some time to load all of the data into memory.
Couchbase Server 2.0 provides a more optimized warmup process; instead of loading data sequentially from disk into RAM, it divides the data to be loaded and handles it in multiple phases. Couchbase Server is also able to begin serving data before it has actually loaded all the keys and data from vBuckets. For more technical details about server warmup and how to manage server warmup, see Section 5.1, “Handling Server Warmup”.