MongoDB 3.4.0-rc3 Fails Jepsen Consistency Testing
Jepsen analysis of MongoDB’s 3.4.0 release candidate uncovered serious replication flaws. Collaborating with MongoDB engineers on a new test design, Kyle Kingsbury found both protocol-level design defects in the legacy v0 replication scheme and separate implementation errors in the newer v1 protocol. Both fault classes could cause loss of updates that had already reached majority commit status.
MongoDB has since shipped fixes for the v1 issues in versions 3.2.12 and 3.4.0, which now pass the broader Jepsen suite. However, the v0 protocol remains vulnerable. Full technical details are available in the official report.
