SQL Server tuning: Disk queue to OS drive: How to optimize? I expect to see the disk queue move on the data, tempdb, log and backup volumes.

I do not expect to see the OS drive (C:) which has zero SQL files present, show disk queue impact.

Assume it is to the OS paging file, or ?

Suggestions on how to chase?

This is SQL 2014 on Win2012-R2/
Use Microsoft Performance Analyzer or Media Experiance Analyzer with Windows Performance Recorder. Any of these is capable of answering your question in great detail, quickly and foul-proof, using system ETW capabilities.

This article is a good walk through: Analyzing Storage Performance using the Windows Performance Analysis ToolKit.

At the simplest, it will be something like this:

c:\&gt;Xperf -on FileIO+Latency+DISK_IO+DISK_IO_INIT+SPLIT_IO
 # repro your scenario
c:\&gt;Xperf -d repro.etl
c:\&gt;Xperf repro.etl


Use the Hard Faults view to track paging spikes, use Disk Utilization to correlate paging and disk IO, use Disk Utilization per Process to identify disk users. 

You can take it one step further with Windows Performance Analyzer, WPA can open the same .etl file Xperf Viewer can, but it has much nicer graphs and intelligence built-in.