Back office ops · Production

Cannes: How Dropbox ML saves $1.7M a year on document preview pre-warming

The problem

Dropbox's Riviera system pre-warmed previews for all eligible files, but a significant portion of that pre-generated content was never viewed, generating considerable and unnecessary CPU and storage costs at petabyte scale.

Workflow diagram · grounded in source
1
File enters pre-warm path
trigger
“Receive file id from Riviera pre-warm path. Riviera collects all file ids eligible for pre-warm. Riviera sends a prediction request with the file id we need a prediction for and the file type.”
2
Retrieve live activity signals
integration
“we use an internal service named the Suggest Backend. This service validates the prediction request, then queries for the appropriate signals relevant to that file. Signals are stored in either Edgestore (Dropbox's primary metadata stora…”
3
Encode signals and predict usage
ai_action
“The collected signals are sent to the Predict Service, which encodes the raw signals into a feature vector representing all relevant information for the file, then sends this vector to a model for evaluation. The model uses the feature v…”
4
Pre-warm routing decision
routing
“This prediction is then sent back to Riviera, which pre-warms files likely to be previewed up to 60 days in the future.”
5
Log request for monitoring
feedback_loop
“Suggest Backend logs the feature vector, prediction results, and request stats—critical information for troubleshooting performance degradation and latency issues.”
Reported outcome

Cannes replaced an estimated $1.7 million in annual pre-warm costs with $9,000 in ML infrastructure per year after being deployed to almost all Dropbox traffic, with no observed degradation to preview latency.

Reported metrics
Annual pre-warm cost replaced$1.7 million
ML infrastructure cost per year$9,000
Offline prediction accuracy>70%
Pre-warm requests rejected by modelabout 40%
Reported stack
RivieraSuggest BackendUser Profile ServicePredict ServiceStormcrowGrafanaSupersetRocksDBHive
Source
https://dropbox.tech/machine-learning/cannes--how-ml-saves-us--1-7m-a-year-on-document-previews
Read source ↗

Frequently asked questions

What did this team achieve with this AI workflow?

Cannes replaced an estimated $1.7 million in annual pre-warm costs with $9,000 in ML infrastructure per year after being deployed to almost all Dropbox traffic, with no observed degradation to preview latency.

What tools did this team use?

Riviera, Suggest Backend, User Profile Service, Predict Service, Stormcrow, Grafana, Superset, RocksDB, Hive.

What results were reported?

Annual pre-warm cost replaced: $1.7 million; ML infrastructure cost per year: $9,000; Offline prediction accuracy: >70%; Pre-warm requests rejected by model: about 40% (source-reported, not independently verified).

How is this back office ops AI workflow structured?

File enters pre-warm path → Retrieve live activity signals → Encode signals and predict usage → Pre-warm routing decision → Log request for monitoring.