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rocks_spool_estimate_pending_compaction_bytes

Type: Gauge
Labels: path
Estimated total bytes that compaction needs to rewrite to bring all levels back under their target sizes.

Info

This metric has labels which means that the system will track the metric for each combination of the possible labels that are active. Certain labels, especially those that correlate with source or destination addresses or domains, can have high cardinality. High cardinality metrics may require some care and attention when provisioning a downstream metrics server.

Since: Dev Builds Only

The functionality described in this section requires a dev build of KumoMTA. You can obtain a dev build by following the instructions in the Installation section.

This is a backlog indicator. Steady-state values depend heavily on write rate, compression, and the configured compaction style, so absolute thresholds should be derived from each deployment's baseline. Unbounded growth over a multi-hour window indicates that compaction cannot keep up with the write rate, which eventually leads to write slowdown (rocks_spool_actual_delayed_write_rate becomes non-zero) and then to write stop (rocks_spool_write_stopped becomes 1).

Only meaningful for level-style compaction.