Changing access log settings

Couchbase Server has an optimized disk warmup. Couchbase Server pre-fetches a list of most-frequently accessed keys and fetches these documents first. The server runs a periodic scanner process which determines which keys are most frequently-used. The cbepctl flush_param command is used to change the initial time and the interval for the process. You may want to do this, for example, if you have a peak time for your application when you want the keys used during this time to be quickly available after server restart.

Note: If you want to change this setting for an entire Couchbase cluster, you will need to perform this command on per-node and per-bucket in the cluster. By default, any setting you change with `cbepctl` will only be for the named bucket at the specific node you provide in the command. This means that if you have a data bucket that is shared by two nodes, you will nonetheless need to issue this command twice and provide the different host names and ports for each node and the bucket name. Similarly, if you have two data buckets for one node, you need to issue the command twice and provide the two data bucket names. If you do not specify a named bucket, it will apply to the default bucket or return an error if a default bucket does not exist.

By default the scanner process runs once every 24 hours with a default initial start time of 2:00 AM UTC. This means after you install a new Couchbase Server 2.0 instance or restart the server, by default the scanner will run every 24- hour time period at 2:00 AM GMT and then 2:00 PM GMT by default. To change the time interval when the access scanner process runs to every 20 minutes:

> ./cbepctl hostname:port -b bucket_name -p bucket_password set flush_param alog_sleep_time 20

To change the initial time that the access scanner process runs from the default of 2:00 AM UTC:

> ./cbepctl hostname:port -b bucket_name -p bucket_password set flush_param alog_task_time 23

In this example we set the initial time to 11:00 PM UTC.

Important: Be aware that this tool is a per-node, per-bucket operation. This means that in order 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 applies the setting to any default bucket that exists at the specified node. In order to perform this operation for an entire cluster, perform the command for every node/bucket combination that exists for that cluster.