PlanetScale's 50 GB/s backup system: how sharded Postgres backups scale to petabytes

Massively Parallel Postgres Backups

PlanetScale's sharded Postgres databases back up at over 50 GB/s, enabling petabyte-scale backups in hours. The system spins up temporary EC2 instances per shard, restores the previous backup from S3, replays WAL from a mix of S3 and the primary, and saves the new backup. This parallelism makes backup speed scale with shard count: a 32 TB database on 8 shards backs up in ~2.8 hours, while 100 TB on 100 shards matches the speed of 1 TB on one shard. Backups also power everyday operations like resizing and node replacement.