Meet Chrono, our scalable, consistent, metadata caching solution

Meet Chrono, our scalable, consistent, metadata caching solution

摘要

Efficiently storing and retrieving metadata has long been a core focus for metadata teams at Dropbox, and in recent years we've made significant improvements to our foundational layer. By building our own incrementally scalable key-value storage, we’ve been able to avoid necessary doubling of our hardware fleet. As we scale, our evolution continues—but there are still challenges we cannot ignore.

At our current rate of growth, we knew there would come a time when the volume of read queries per second (QPS) could not be sustainably served by our existing underlying storage machines. Caching was the obvious solution—but not necessarily an easy one.