The Dropbox Traffic team is charged with innovating our application networking stack to improve the experience for every one of our users—over half a billion of them. This article describes our work with NS1 to optimize our intelligent DNS-based global load balancing for corner cases that we uncovered while improving our point of presence (PoP) selection automation for our edge network. By co-developing the platform capabilities with NS1 to handle these outliers, we deliver positive Dropbox experiences to more users, more consistently.
Spoiler alert: BBRv2 is slower than BBRv1 but that’s a good thing.
BBRv1 Congestion Control
Three years have passed since “Bottleneck Bandwidth and Round-trip” (BBR) congestion control was released. Nowadays, it is considered production-ready and added to Linux, FreeBSD, and Chrome (as part of QUIC.) In our blogpost from 2017, “Optimizing web servers for high throughput and low latency,” we evaluated BBRv1 congestion control on our edge network and it showed awesome results:
Since then, BBRv1 has been deployed to Dropbox Edge Network and we got accustomed to some of its downsides.
In the past few months, we have gradually enabled IPv6 for all user-facing services in Dropbox edge network. We are serving about 15% of daily user requests in IPv6 globally. In this article, we share our experiences and lessons from enabling IPv6 in the edge network. We will cover the IPv6 design in the edge, the changes we made to support IPv6, how IPv6 was tested and rolled out to users, and issues we encountered. Note that this article is not about enabling IPv6 for internal services in our data centers, but rather focuses on making IPv6 available to users.
Update (November 14, 2017): Miami, Sydney, Paris, Milan and Madrid have been added to the Dropbox Edge Network.
Since launching Magic Pocket last year, we’ve been storing and serving more than 90 percent of our users’ data on our own custom-built infrastructure, which has helped us to be more efficient and improved performance for our users globally.
But with about 75 percent of our users located outside of the United States, moving onto our own custom-built data center was just the first step in realizing these benefits. As our data centers grew,