rocks_spool_load_shed_active

Type: Gauge
Labels: path

Set to 1 when this spool's load-shedding gate is latched, 0 otherwise. When set, ingress paths (SMTP, HTTP inject) reject traffic and foreground store/remove operations fail fast rather than stall.

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.

The gate latches in either of two ways:

• Immediate: a foreground spool operation (load, store, remove) returns a rocksdb error classified as definitively bad (Corruption or IOError -- e.g. a missing or corrupt SST file discovered during a read). These conditions have no transient interpretation, so the gate latches on the first such observation.
• Debounced: less specific failure signals -- background-errors has grown since this process started, or foreground operations have returned non-fatal errors -- sustained continuously for the configured error_latch_duration (default 15s). This filters out brief auto-resumed errors.

If allow_error_unlatch is enabled (the default), the gate auto-clears after error_unlatch_duration of observed recovery (default 5 minutes) with no new errors of either class. Otherwise it stays set until the process is restarted.

SREs should treat any sustained non-zero value as an operator-actionable incident; pair this metric with rocks_spool_background_errors to understand why.