When is a peak not a true peak?
One common requirement I get from customers is the need to size for peaks. I've seen many mistakes in defining what a peak actually is.
So, let's elaborate on peaks.
How do you define peak utilization or contention without being overly conservative or aggressive?
There are two dimensions of peaks: you can measure them across time or across members of the group.
Let's take a cluster with eight ESXi hosts as an example. The following chart shows the ESXi Hosts Utilization for the eight hosts.
What's the cluster peak utilization on that day?
The two dimensions of peaks
As you can see from the graphs, it is not so simple. Let's elaborate:
- Approach 1: You measure across time. You take the average utilization of the cluster, roll up the time period to a longer time period, and calculate the peak of that longer time period. For example, the average cluster utilization peaks at 65 percent at 9:05 am. You roll up the data for one day. This means the...
