I've found the following information about the Historical Metrics limitation inside the Bookshelf version 9.5.x
Note about introscope.enterprisemanager.metrics.historical.limit:
The default value of the introscope.enterprisemanager.metrics.historical.limit property is set to 1.2 million. This value can be increased to 5 million without any significant performance impact. (74765, 76890)
This info means that the EM supports 5 million instead of 1.2 million OR the value only can be increased into 5 million?
I've installed 9.7 version and each Collector have 2.5 million historical metrics and I have peaks of Smartstor Duration constantly ( >3500ms).
I'm doing the parallel investigation about the I/O but one of the problems with Smartstor duration is Metrics overload.
I need to be worry about the 2.5 million historical metrics using the 9.7 version?