How do you troubleshoot unbalanced load across brokers?

Check the cluster's current bundle-to-broker assignment and per-broker resource metrics (CPU, throughput, connection count) via pulsar-admin or a monitoring dashboard to confirm the imbalance is real and see which brokers are over- or under-loaded.

A common cause is a small number of very hot bundles sitting on the same broker; check whether automatic bundle splitting is enabled and whether its thresholds are appropriately tuned for the actual traffic pattern - overly conservative thresholds delay splitting hot bundles.

Confirm the load manager's shedding configuration is active - Pulsar's load manager can actively unload bundles from overloaded brokers onto less-loaded ones, and if this is disabled or too conservative, imbalance can persist even after hot bundles are correctly split.

Check for "sticky" traffic from non-partitioned topics: a single very high-traffic non-partitioned topic is inherently confined to one broker, since it can't be split across brokers the way a partitioned topic can - if that's the imbalance source, converting it to a partitioned topic is the actual fix, not load-manager tuning.

Finally, verify client-side connection distribution isn't itself skewed, for example a proxy or DNS layer routing disproportionately to a subset of brokers, since load imbalance can sometimes originate outside Pulsar's own load manager entirely.