IBM Support

FlashSystem canister report high CPU usage after firmware update

Troubleshooting


Problem

The client is reporting a high canister CPU usage above 95% from IBM FlashSystem-900 after firmware update to either 1.5.2.5  or higher /1.6.1.0 or higher.
The CPU usage is typically reported by the client monitoring software.

Symptom

The FlashSystem-900 reporting a good health status. There are no evidence for any problem inside the FlashSystem-900.
However, client monitoring software may report a significant canister SYS CPU usage since firmware update.
The total canister CPU usage is permanent above 95%.
image-20191018111038-1

Cause

Current investigation has not found any functional software issue. 
Development assume this to be a bug in the Linux CPU utilization reporting.

Resolving The Problem

FlashSystem-900 I/O path is fully separated from the management CPU in the canister and can live with any CPU load.
The canister CPU is only needed for management tasks and some internal tasks from SVC code  layer. 

The FlashSystem-900 is designed to be enterprise-grade storage system running for multiple years at continuous 100% capacity, 100% load, even when the ambient data center temperature is up to 35 degrees C.
In addition, the canister CPU are pretty weak and expected to produce only a minimal fraction of heat, compared to the flashmodule which are the major source of heat in the IBM FlashSystem-900.

We understand that seeing 100% CPU utilization in stats can be very confusing for the client. However, high canister CPU activity is not related to any of I/O or management activity so those tasks will not be affected. Also maintenance operations will not be affected as well. 

Document Location

Worldwide

[{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"STKMQB","label":"IBM FlashSystem 900"},"Component":"","Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"1.5.2.5, 1.6.1.0","Edition":"","Line of Business":{"code":"LOB26","label":"Storage"}}]

Document Information

Modified date:
27 December 2019

UID

ibm11089022

Page Feedback