Device data collection using DEVSSCHR Performance Concerns

Products

• SYSVIEW Performance Management

Issue/Introduction

We're looking into letting SYSVIEW alerting us of device i/o rate using mvs threshold over DEVSSCHR variable.

However we noticed that the data collector for device metrics and this variable is not enabled by default.

Could you please help advise why is that and is there any performance concerns or other problems if we enable it?

 

Environment

Release : 16.0

Component : SYSVIEW

Resolution

Sysview is intentionally distributed with parameters, etc ‘turned off’ so as not to create a potential surge in overhead. 

The DEVSSCHR parm measures the SSCH instruction rate for the device.   Turning it on uses overhead, and will cause the threshold to be measured according to your THRESHold settings.  Although we have not had any reports of problems caused by this particular variable, we advise that you closely monitor CPU overhead when you first turn it on.   You may find that you need to adjust the MVSDATA-DEVICES SCHEDULEd frequency to run less or more frequently.  Obviously, the more frequently it runs the greater the CPU utilization.