Unplugging the Hydra-Booster DB
Dennis Trautwein
About this talk
A PL Demo Day 2022 update on the decision to "unplug" the shared database behind Protocol Labs' Hydra Booster fleet, which at the time consisted of around 135 Hydras with roughly 2,000 heads making up about 12% of the IPFS DHT. Dennis explains that the heads were retained for their network-bridging role but stripped of provider-record storage and serving to cut operating costs, with a preceding A/B experiment running two six-node Kubo fleets across regions — one ignoring Hydra responses, one not — to estimate the latency impact at the 50th, 90th, and 95th percentiles. After the cutover on December 1st, observed retrieval latency degraded slightly more than predicted, partly because skipping non-responsive Hydras still costs an extra DHT hop. The change yielded roughly 36% cost savings, with AWS egress (largely TCP handshakes, RTTs, and multistream-select negotiation) identified as the next-largest remaining cost driver and a candidate for further optimization.