Snowcannon: Synchronous Data Replication in FDB - Markus Pilman + David Youngworth

The current FDB disaster recovery solution uses asynchronous replication, therefore failover might result in data loss.

For Snowflake, this is an unacceptable business risk.

Snowcannon is a synchronous, distributed queueing system built within FDB. An FDB cluster can synchronously replicate transactions to Snowcannon, and Snowcannon asychronously pushes these transactions to a secondary cluster. The queueing system has three benefits: (1) It can replay rollbacks and redos (2) It allows us to bring down the secondary cluster for maintenance while the primary remains online. (3) In the event that both primary and secondary cluster fails, it allows recovery from backups with zero data loss.

This talk will go over the design of Snowcannon, including the replication protocol, failover switch, queueing architecture, and the quorum protocol.