Читать книгу CompTIA Cloud+ Study Guide - Ben Piper, David Higby Clinton - Страница 106

Before migrating to the cloud, you should establish baselines for various aspects of your current infrastructure. Baselines to collect include CPU, memory, storage utilization, and database query times. Establishing baselines helps you determine how to size your cloud resources. Baselines also help you tune your monitoring. Use your baseline statistics as a reference, and if a metric goes significantly above or below that value, you can configure an alert to fire or autoscaling to add more capacity. The deviation of a metric from a baseline is called variance.

Because the metrics you'll be monitoring will likely change quickly, minute by minute, as well as slowly over longer periods of time, you'll want to take baseline samplings for both long-term and short-term intervals. For example, suppose a database server running in your data center averages 70 percent CPU utilization over the course of a day, but it occasionally spikes to 90 percent for about 15 minutes when someone runs a complex query. You don't necessarily want to alert every time the CPU utilization spikes. But you might want to know if the average daily CPU utilization begins creeping up to, say, 80 percent. Therefore, having separate baselines for the long term and the short term gives you a better picture of what's really going on in your environment. Keep in mind that monitoring always requires trial and error.

Your baselines help you form a starting point for determining what the normal metrics are for your environment, but they're not to be taken as gospel, since they will change over time. Also, given the huge number of cloud resources available, there are even more metrics that you can monitor. The key is to focus only on the most impactful metrics.