Understanding Dble Startup Configuration Validation and Common Failure Cases (Version 3.22.01.0)

This article is dedicated to newcomers of Dble, explaining why startup failures often stem from incorrect configuration and how Dble validates its configuration files during launch, using version 3.22.01.0 as an example.

It first lists the four types of configuration files located in the conf directory—*.cnf, *.xml, *.properties, and *.txt—detailing the purpose and key considerations of each file such as cluster.cnf , bootstrap.cnf , user.xml , db.xml , sharding.xml , and various sequence and cache files.

Next, the article presents several typical startup failure scenarios, showing the problematic bootstrap.cnf or db.xml contents, the corresponding error messages extracted from wrapper.log , and step‑by‑step troubleshooting actions: correcting port conflicts, removing illegal spaces, fixing data‑type mismatches, using correct property names, adjusting MySQL version strings, and ensuring backend MySQL connectivity and case‑sensitivity consistency.

Additional checks include validation of sharding algorithms, user‑type and instance‑group pairing, and maxPacketSize synchronization. The article concludes that Dble performs comprehensive legality checks on all configuration files and backend nodes, and most startup issues can be resolved by following the error hints in the log.