The MongoDB team rewrote their database backup utility, mongodump, to support high-throughput concurrent workloads while maintaining its serial output. To achieve this, they utilized Golang constructs like reflection and channels to safely permit multiple goroutines to concurrently feed data into the archive. The new archive format interleaves slices of data from collections, allowing for concurrent backups of multiple databases and collections to a single file. A multiplexer is used to manage the concurrency by selecting input sources based on their readiness, using a control channel to signal completion or changes in the select cases. This design enables efficient streaming of backups over networks or into another instance as part of a load operation. The new tool is faster, simpler, and more featureful than its predecessor, thanks to Golang's powerful concurrency features.