Typically you may have seen the TIBCO Spotfire Web Player instance get to the STRAINED health status if the either the RAM or CPU utilization go above the limits mentioned here in the documentation for Spotfire.Dxp.Worker.Host.exe.config file.  But in some cases you may notice the Web Player instance health be marked as STRAINED even though there is no issue with the RAM and CPU on the Spotfire Node Manager machine. 
 

In versions 7.5 to 7.13, the the Health Status was calculated based on the CPU and RAM only, but starting with Spotfire version 7.14 the available temp disk space, high degree of data paging to disk, and WCF network traffic settings have also been added as factors in the health calculation and are configured in the Spotfire.Dxp.Worker.Host.exe.config file

So now you may see instances be strained or exhausted due to CpuStatus, MemoryStatus, PagingStatus, WcfStatus, or DiskStatus:

Health_UsePagingForHealth	
Health_UseTempDiskForHealth	
Health_UseWcfStatsForHealth	
Health_ExhaustedTempDiskMb	
Health_LogWarnTempDiskMb
Health_StrainedTempDiskMb
Health_LogDebugTempDiskMb	
Health_WcfCallsPerCoreExhausted
Health_WcfCallsPerCoreStrained
Health_RecentPagingMinutes
Health_StrainedRecentPagingOutShareOfHeapPercentage (or 
Health_StrainedRecentPagingInShareOfHeapPercentage for paged in data)
Health_StrainedRecentPagingOutShareOfHeapPercentage
Health_StrainedRecentPagingInShareOfHeapPercentage

For a description of these settings, and to see their default values, see the Spotfire.Dxp.Worker.Host.exe.config documentation.

The following is an example of what is logged (in Spotfire.Dxp.Worker.Host.Debug.log) when the Web Player status changed to STRAINED status due to the Tempdisk limit being reached i.e the amount of free MB temp disk space is 11207MB which is below the limit 16000:

DEBUG;2019-05-06T15:27:51,293+00:00;2019-05-06 15:27:51,293;786adabc-58c2-4dc5-9a50-d4657f2fbdad;061527c777vM9B;4;monitoring@SPOTFIRESYSTEM;MonitoringUserSession;Spotfire.Dxp.LifeCycleEvents;"Send life cycle event synchronously 'MemoryStatusChangedMonitoringEvent: Status Strained, CpuStatus Ok, MemoryStatus Ok, PagingStatus Ok, WcfStatus Ok, DiskStatus Strained, AverageCpuUsage 0, AverageInstanceCpuUsage 0, AverageNodeCpuUsage 0, CurrentInstanceCpuUsage 0, CurrentNodeCpuUsage 0, MemoryAvailablePercentage 95, MemoryAvailableMb 61487, CurrentInstanceMemoryUsage 270532608, CurrentInstanceMemoryUsagePercentage 0.4, AvailableDiskMb 11207, OutstandingWcfCalls 0, CachedDocuments 0, OpenDocuments 0, CurrentRunningQueries 0, AvailableScheduledUpdatesSlots 2, MaxScheduledUpdatesSlots 2, Explanation Health status is Strained and the amount of free MB temp disk space is 11207 which is below the limit 16000..', to 'https://ip-172-31-30-186.ec2.internal:9443/spotfire/nodemanager/messages'."

This article explains why the TIBCO Spotfire Web Player instance shows as STRAINED in Monitoring & Diagnostics even though the Node Manager machine does not have high RAM or CPU utilization

Doc: Spotfire.Dxp.Worker.Host.exe.config

• https://docs.tibco.com/pub/spotfire_server/12.0.0/doc/html/TIB_sfire_server_tsas_admin_help/server/topics/spotfire.dxp.worker.host.exe.config_file.html