L2 finalization has not moved on L1
criticalreviewed 2026-10-13What it meansmoreThe rollup's finalized block on L1 has not advanced for 20 minutes while the L2 head moved. The settlement pipeline is conflation → proving → aggregation → blob submission → finalization on L1; one stage is flat. In both past cases the flat stage was proving (see the prover-oom-loop runbook).
ImpactmoreWithdrawals cannot be claimed on L1 until finalization catches up; the settlement-freshness SLO burns fast. SEV2. SEV1 if signing keys or L1 submission are failing (funds at risk), not just slow.
Quick mitigation0/4
Find the flat stage on the Settlement pipeline panel (L2 Settlement dashboard)
If proving is flat or
LinethL2ProverLargeRetry fires: follow prover-oom-loopIf blob submission is flat: check web3signer (L2 signing keys loaded) and L1 besu
Post the first status update with the finalized block and head lag
Diagnosis3 queries
Lag between the L2 head and the finalized block:
max(lineth_l2_head_block) - max(lineth_l2_rollup_finalized_block{l1_block_tag="latest"})Finalized block movement in the last 15 minutes (0 = flat):
increase(lineth_l2_rollup_finalized_block{l1_block_tag="latest"}[15m])Coordinator backpressure or submission errors:
{namespace="lineth-l2", pod=~"coordinator-.*"} |~ "(?i)gapOverflow|backpressure|error"Fix0/2
Fix the flat stage at its cause (prover memory, signer, L1 node), not by restarting the coordinator
Alert on the proven gap approaching
bonsai-historical-block-limit (PM-11 A10)Escalation
If no stage is visibly flat, or finalization does not move within 30 minutes of the mitigation, write a checkpoint with a wake condition on the finalized block and hand over with the hypotheses tried.
Seen in INC-2026-10-11-08, INC-2026-10-11-11 · SLOs settlement-freshness, withdrawal-1h · owner s1ns3nz0