A connect string option is required in order to connect to Couchbase. This can be specified with --connect on the command line. Below are two examples of connect strings.

http://10.2.1.55:8091/pools
http://10.2.1.55:8091/pools,http://10.2.1.56:8091/pools

When creating your connect strings simply replace the IP address above with the IP address of your Couchbase sever. If you have multiple servers you can list them in a comma-separated list.

Why list multiple servers? Let's say you create a backfill stream for 10,080 minutes or one week. In that time period you might have a server crash, have to add another server, or remove a server from your cluster. Providing an address to each server allows an import and export command to proceed through topology changes to your cluster. In the first example above if you had a two-node cluster and 10.2.1.55 goes down then the import will fail even though the entire cluster didn't go down. If you list both machines then the import will continue unaffected by the downed server and your import will complete successfully.