Due to organizational issues I've inherited some 3PAR systems (8400/7400/7200) running production workloads for lots of customer. Fairly experienced in IT, I do not have a lot of experience with system administration of 3PAR systems itself. So, sorry for being noob in such an experienced User Group, I really hope anyone can answer some questions.
Recently I've expanded storage capacity of one of the 3PAR systems by adding 8x SSD in a 2 node system. There were already 20 SSD in each prior to the expansion.
Last week we were notified that there are latency issues on some parts of our virtualized environment (vSphere 5.5). Further investigation lead into a hypothesis that this could be due to unevenly distributed requests on the storage layer. Because the older drives are stuffed over 97% most of the new (write) requests will pass to only the new drives (8x).
Reading this forum and sites like
https://d8tadude.com/2014/06/06/disk-load-and-tunesys/ hint me in doing a system tune, so data will be evenly balanced across the system. To add to the hypothesis: this tune will balanced data evenly, so requests will be routed more spread than the current high density on the new drives. This would lead to less latency problems.
That for a situational overview given I have to following questions:
- Is there any risk for my production workload in running a system tune?
- Can anyone confirm or correct my hypothesis with arguments, so I can learn something about the inner working?