A Prysm node and a Lodestar node on the same chain, on identical hardware, both export beacon_reorgs_total. Over the last 90 days, the Prysm hosts in our Vienna NDC2 fleet incremented that counter 6,011 times. The Lodestar hosts incremented it zero times. Both numbers are correct readings of what each implementation chose to count.

This post is a 90-day reorg census across that fleet plus the smaller GCP comparator cohort: every consensus client (CC) paired with every execution client (EC), against the same Ethereum mainnet, with per-host normalization. The questions we answer: which Prometheus counter to trust for which question, why the same EC behind two different CCs produces very different reorg numbers, and why a "zero reorgs" reading on some clients is silence rather than safety.

Key findings at a glance:

• Prysm increments beacon_reorgs_total 8× more often than Lighthouse over 7 days. The gap shrinks to 1.6× over 90 days.
• Lodestar's beacon_reorgs_total is 0 for the entire 90-day window. Its decline-reason counter fires roughly 54 times per host per week.
• The same EC behind two CCs produces 2–5× different counts: Prysm + Besu reports 69 per host vs Prysm + Nethermind 280.
• Geth is the only EC in our fleet whose Prometheus reorg counter increments at all. Nethermind and Reth export the metric but it never increments; Besu, Erigon, and Ethrex don't export one at all.
• A single fixed beacon_reorgs_total alert threshold does not port between consensus clients. Re-baseline per CC × EC pair.

Ethereum runs on two layers: an execution client (EC) handles the EVM, transactions, and world state, and a consensus client (CC) handles Proof-of-Stake fork choice and validator duties. Six EC implementations and seven CC implementations exist in production today, paired in dozens of combinations across the network. StereumLabs runs all of them, side by side, on identical hardware in our Vienna data center, and publishes the numbers.

This post is the technical introduction to that platform: the bare-metal fleet, the metrics and logs pipeline, the label conventions that make the pairings comparable, and the in-house AI workflow that turns the resulting telemetry into the blog posts you are reading.

RockLogic publishes a separate case study on the business side of this workflow: how the same "AI on own data" pattern keeps customer telemetry inside the perimeter while still producing useful answers. This post is the technical view from the other side of the same workflow.

Before The Merge in September 2022, an Ethereum node was a single Proof-of-Work client. Geth, Parity, Erigon, Nethermind, or Besu, each handling everything from networking and the EVM to mining and chain selection inside one binary. The Merge split that role in two: an execution layer (EL) for the EVM, transactions, mempool, and world state, and a consensus layer (CL) for Proof-of-Stake fork choice, finality, attestations, and block proposals. The two halves talk to each other over the engine API, a JSON-RPC channel authenticated with a JWT secret.

Most operators run those two layers as two separate binaries that talk over the engine API. Caplin v3.3.10 collapses them back into a single Erigon binary. We added a Caplin standalone host to the StereumLabs fleet on April 8, 2026, and let it run alongside the classic Erigon plus CC pairings under identical mainnet conditions. This post reports what we measured: where the monolithic architecture wins, where it pays a tax, and where it leaves observability holes.

Every execution client connects to different peers, sees a different slice of the network, and churns through connections at wildly different rates. We queried Prometheus metrics and Elasticsearch container logs across our entire fleet to find out what each EC actually experiences at the P2P layer, and what it means for Ethereum's network health.

We measured gossip verification, KZG batch verification, data column reconstruction, and getBlobsV2 latency across 72 nodes running all six consensus clients. The verification speed spread between fastest and slowest client: 50x.

We deployed all 6 Ethereum execution clients from scratch on bare metal and tracked exactly how long each one took to fully sync. The results range from impressive to alarming.

How does each execution client behave when Nimbus asks it to build a block? We monitored 1,000 validator pubkeys across 5 EC pairings for 48 hours and found that block building performance varies dramatically, with one client producing near-empty blocks while the other four packed in millions of gas.

A deep dive into how Teku evolved across three releases: the RocksDB migration in 26.2.0, jemalloc in 26.3.0, and what both changes mean for CPU, memory, GC overhead, disk I/O, and block import latency on real hardware.

A recap of our EthCC[9] presentation in Cannes: what StereumLabs is, how we use AI on top of our monitoring data, and what Fusaka actually did to hardware across 36 client pairings.

We measured CPU, memory, disk I/O, and network across all 36 CC×EC pairings on our non-supernode fleet — here's what the Fusaka hardfork actually did to hardware consumption.