Elasticsearch's version 6.1 introduces an on-demand forecasting feature as part of its X-Pack machine learning capabilities, enabling users to predict future data trends based on historical data. This feature allows for capacity planning, such as estimating server disk space needs or predicting customer call volumes, by analyzing past performance indicators. Users can access forecasting through the Single Metric Viewer, where they can initiate forecasts and view results represented by trend lines and confidence bands. The accuracy of forecasts depends on various factors, including the amount of historical data available—ideally at least three weeks—and the maturity of the machine learning model. Forecasts come with unique identifiers and are automatically deleted after 14 days when run via the UI, although API usage permits customization of data retention durations. Elastic's machine learning tools require a Platinum subscription, but a free trial of X-Pack is available for new users.