If a Couchbase Server node is starting up for the first time, it creates any database files that are necessary and begins serving data immediately. However, if there is already data on the disk, usually because the node rebooted or the service restarted, the node needs to read all of this data of the disk before it can begin serving data. This process is called warmup and it can take some time depending on the size of the data.
Syntax to check statistics related to the node warmup :
cbstats [host]:[dataport] -b [bucket_name] -p [bucket_password] raw warmup
cbstats 188.8.131.52:11210 warmup
ep_warmup: enabled ep_warmup_dups: 0 ep_warmup_estimate_time: 57546 ep_warmup_estimated_key_count: 0 ep_warmup_estimated_value_count: unknown ep_warmup_key_count: 0 ep_warmup_keys_time: 529022 ep_warmup_min_items_threshold: 100 ep_warmup_min_memory_threshold: 100 ep_warmup_oom: 0 ep_warmup_state: done ep_warmup_thread: complete ep_warmup_time: 529192 ep_warmup_value_count: 0
See more about cbstats warmup stats