One of the most important use cases for the cbepctl flush_param is the set the time interval for disk cleanup. Couchbase Server does lazy expiration, that is, expired items are flagged as deleted rather than being immediately erased. Couchbase Server has a maintenance process that will periodically look through all information and erase expired items. This maintenance process will run every 60 minutes, but it can be configured to run at a different interval. For example, the following options will set the cleanup process to run every 10 minutes:

./cbepctl localhost:11210 -b bucket_name -p bucket_password set flush_param exp_pager_stime 600

Be aware that this tool is a per-node, per-bucket operation. That means that if you want to perform this operation, you must specify the IP address of a node in the cluster and a named bucket. If you do not provided a named bucket, the server will apply the setting to any default bucket that exists at the specified node. If you want to perform this operation for an entire cluster, you will need to perform the command for every node/bucket combination that exists for that cluster.

Here we specify 600 seconds, or 10 minutes as the interval Couchbase Server waits before it tries to remove expired items from disk.