How to Estimate Storage Needs for Google Photos: A Guide for Product Management Interviews

Introduction

When preparing for a product management interview at a FAANG company, candidates often encounter questions that test their analytical and estimation skills. One such question aspiring product managers might face is related to estimating storage needs for a popular service like Google Photos. Being able to answer these types of questions effectively is critical as it shows the ability to think quantitatively and strategically about product-related challenges. In this post, we will tackle the question: How would you go about estimating the amount of storage needed for Google Photos?

Detailed Guide on Framework Application

Selecting a Framework

The framework that we’ll use to structure our answer is called the Fermi Estimation technique. This method, named after physicist Enrico Fermi, involves breaking down complex problems into smaller, more manageable parts that we can more easily estimate.

Step-by-step Guide

1. Define the scope: Clarify whether you’re estimating storage for all users globally or for a specific period.
2. Make assumptions: Begin with assumptions about the average number of users, number of photos taken, and average file size per photo.
3. Calculate individual storage: Estimate the storage needed for one user by multiplying the average number of photos by the average file size.
4. Scale up: Extend the calculation to the assumed total user base to estimate overall storage.
5. Consider growth: Account for the growth in users and advancements in camera technology which might affect the average file size.
6. Apply data reduction strategies: Factor in Google’s data compression and deduplication techniques which can reduce the required storage.
7. Provide a range: Present your answer as a range to account for the variability and uncertainty in your assumptions.

Hypothetical Examples

Let’s assume we have 1 billion users with each user uploading 500 photos per year at an average file size of 2MB per photo. Calculating for one user, we’d need 1GB of storage annually. Scaling this up, Google Photos would require about 1 exabyte of storage each year. But, after accounting for data compression, say at a factor of 50%, the storage need could be reduced to 500 petabytes per year.

Facts Checks and Approximations

While the actual numbers may be proprietary to Google, we can base our assumptions on publicly available data such as the number of smartphone users or the average number of photos taken by an individual per day.

Effective Communication Tips

When verbalizing your answer, do so in a systematic and confident manner, showing that you understand each assumption’s impact on your final estimate. Remember, interviewers are more interested in your approach and reasoning skills rather than the exact numbers.

Conclusion

Answering estimation questions in product interviews requires a structured approach that helps you demonstrate analytical proficiency. By practicing the Fermi Estimation method, aspiring product managers can confidently tackle complex problems and impress interviewers with their quantitative reasoning abilities. Remember, the goal is to show that you can think critically and structure your thoughts, so be clear, be concise, and show the rigor in your approach.