Questions for Old Piwik Data

The number of our Piwik data has been grown to 18.5G since the system was installed on our server in 2010.
How can we export the date to my local sever, so I can check the old date anytime and reduce our mySQL space.
For example, How can I export the piwik date to my local sever subject to time?

If it can’t be exported, how can I delete the old data?

Thanks for reading>:D<

See Installation - Analytics Platform - Matomo for moving/ copying the database to another server.
See Troubleshooting - Analytics Platform - Matomo for deleting old reporting data.