Three types of metrics
Define how much of resource is used.
Simple countable things, like errors or users.
Metrics represented by a range of values at any
Good for capacity planning, not so good for
B i n o m i a l D i st r i b u t i o n
Tells us how likely it is to see n successes in a
certain number of trials
How many errors are ok?
Likeliness of at least n errors
18 % probability to see 5 or
more errors. Which is within 2
times Std. Deviation. We do not
Response Time Example
Our median response time is 300 ms
and we measure
Did the median drift
Check all values above 300 ms
7 values are higher than the median. Is this normal?
We can again use the Binomial Distribution
Applying the Binomial
We have a 50 percent likeliness to see values
above the median.
How likely is is that 7 out of 10 samples are higher?
The probability is 17 percent, so we should not alert.
… and we are done!
How to calculate
How to get
How to define that
This was just the beginning
There are many more use things about statistics,
probabilities, testing, ….