I am getting Storage questions incorrect invariably. Can someone explain how to go about in answering questions like
You currently have 300TB of Closed-Circuit Television (CCTV) capture data and are adding new data at a rate of 80TB/month. The rate of data captured and needing to be stored is expected to grow to 200TB/month within one year because new locations are being added, each with 4-10 cameras. Archival data must be stored for six months, and as inexpensively as possible. The users of your system currently need to access 250TB of current-month footage and 50TB of archival footage, and access rates are expected to grow linearly with data volume. Which of the following storage options best suits this purpose?
What is the key here?
1 Answers
Hello! I’m glad you’ve reached out! 🙂
I’ve had some other students say that it really "clicked" for them when they took these practice questions and ran each response option through the GCP Pricing Calculator. I suggest you do this for a couple of questions, to get the practice, and then try to answer things based on what you then understand about the pricing structure.
In particular, you should determine how much data will be stored and retrieved, in each class. Both of those things affect the price, and they affect each storage class differently.
For the question you posted, think about the situation you’ll have in one month:
You’ll have 300TB of archive data.
You’ll have 80TB of new (current month) data.
You’ll retrieve 50TB of archive data.
You’ll retrieve 250TB of new data. (Clearly, you will retrieve some of it multiple times.)
How much (in real dollars) would each storage class cost for each type of data? With that knowledge, which response option is the best? With that understanding, do you see why Google recommends the "retrieved less than once per month" and "retrieved less than once per year" rules of thumb for Nearline and Coldline storage classes? 🙂
Hope this helps!
Mattias