You can configure logging at a few different levels for Couchbase Server:
Couchbase Server logs. The primary source for logging information is Couchbase Administrative Console. The installation for Couchbase Server automatically sets up and starts logging for you. There are also optional, lower level logs which you can configure. For more information, see Couchbase Server Manual, "Troubleshooting."
SDK-specific log errors. For more information, refer to the Language Reference for your chosen SDK.