I am collecting metrics related to memory using api compute.googleapis.com/guest/memory/bytes\_used from google cloud metric explorer. I selected a particular **instanceid** and I set the alignment period to 1 day. so that I will get the metrics for 1 day.
For the same alignement period:

1. In advanced aggregation I selected the **Aligner** as **mean** and i got this value for the **free** category of memory **114.526** KiB

[![First Time](https://i.stack.imgur.com/YIwqE.png)](https://i.stack.imgur.com/YIwqE.png)

2. In advanced aggregation I selected the **Aligner** as **sum** and i got this value for the **free** category of memory **63.750** Mib

[![enter image description here](https://i.stack.imgur.com/lmCNc.png)](https://i.stack.imgur.com/lmCNc.png)

I am not understanding the formulae, on how this align\_mean and align sum is calculated. i have set the alignment period to 1 day. Can anyone give me the forumula and the explanation.

Thanks a lot for your help.