DropBox Removed their SSDs, got 20% faster writes

https://dropbox.tech/infrastructure/increasing-magic-pocket-write-throughput-by-removing-our-ssd-cache-disks

In this episode of the backend engineering show I’ll discuss how Dropbox improved their write through put by 20% by removing all their SSDs (yes I was surprised too). DropBox uses an SSD layer as a write-back cache with SMR drives as their backend persistent storage. They changed their model to write directly to the hard drives.

0:00 Intro

2:00 Article Summary

3:00 SMR Drives

6:00 SSD Cache & WriteBack

8:00 Replacing Cache

9:30 Storage Engine Background

14:30 Why did they do it

15:00 The limitation of SSDs & Zoned Namespaces

19:30 Updating the Storage Engine

22:30 Tradeoffs

26:00 Rollout

28:00 Summary