Hot Swap Your Datastore: A Practical Approach and Lessons Learned

Wednesday, December 09, 2020 - 10:45 am11:25 am

Raj Shekhar and Mehmet Can Kurt, Quantcast


This talk is about how we migrated from an in-house legacy datastore that handles 1.5 million lookup requests (per second) to a more reliable, flexible, and cheaper system.

We will talk about how to achieve three major goals for the migration process:

  • at least similar or better performance than the legacy system
  • ensure the quality and correctness of the data served by the new system, and
  • do the first two without any downtime on production and affecting the company's main revenue generating product.

This talk is aimed at software engineers and site reliability engineers who are thinking of replacing a critical part of their distributed system.

Raj Shekhar, Quantcast

Raj is a Staff System Engineer at Quantcast, working on maintaining the uptime and reliability of the servers tracking Quantcast pixels across the web. He enjoys poking sleeping dragons in large scale distributed systems. When not working, you can find him planning his next getaway, usually to a place accessible by motorcycle.

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@inproceedings {262200,
author = {Raj Shekhar and Mehmet Can Kurt},
title = {Hot Swap Your Datastore: A Practical Approach and Lessons Learned},
booktitle = {SREcon20 Americas (SREcon20 Americas)},
year = {2020},
url = {},
publisher = {{USENIX} Association},
month = dec,

Presentation Video