look at historical metrics count under “Number of historical metrics”. If you see a spike (sudden or consistent) in historical metrics, this indicates historical metrics is growing and will breach its threshold one day. Looking at APM status console will confirm if historical metrics has been breached its threshold value. introscope.enterprisemanager.metrics.historical.limit clamp is a nice indicator to show per EM’s historical limit. The solution for this is to trim excessive metrics from smartstor to provide some space for live metrics flow. We have Smartstor cleanup procedures to achieve this.
here is the KB article to trim smartstor database
How do I cleanup SmartStor data? - CA Knowledge
following link is for CLW command will also help you running some queries.
CLW Command Reference - CA Application Performance Management - 9.7 - CA Technologies Documentation