The sort of latency heat map you don’t want to see!

We’ve had a couple of short lived, but very inconvenient I/O latency issues recently. I’ve been using the awesome Latency Heat Map Visualization by Luca Canali as one of the tools to investigate this.

I’m guessing this isn’t the type of I/O latency heat map most people would want to see from a production system. 🙂



This is the same system that has been reporting Warning “aiowait timed out x times” in alert.log [ID 222989.1], which only appears if an asynchronous I/O takes longer than 10 minutes…

The pictures look much nicer when things are going wrong! 🙂