Overview

This playbook describes how to analyze ingest and read patterns.

Analysis

For this playbook we will use the Harris IT system that has been used in the other Dxi7500 Playbooks.  The purpose of looking Disk I/O is to determine if the disks are too busy:

Acceptable Disk I/O distribution in % is 70%.  According to this graph, the disks in this system are not having a negative impact on performance.  If the data on the Disk I/O distribution in % graph is constantly over 70% then Disk I/O should become a focus of the investigation.

One common factor that can have a negative impact on Disk I/O is the number of streams being used by the backup software.  An excessive number of streams will result in higher than desired disk I/O causing deduplication and GC to slow down significantly.  Other causes of high disk I/O are faulty hardware or the file system not being evenly distributed across the stripe groups.

Conclusion

A Disk I/O distribution in % of lower than 70% can typically be ignored.  Anything higher should demand attention to the I/O while keeping all of the other pieces of the methodology in mind.