Use an authorized, reachable Broker to create a safe 25-client Fan-out baseline, pass Preflight, and verify live MQTT traffic in five minutes.
Loading...
Create a small, repeatable MQTT benchmark with one Publisher and 24 Subscribers. Connect your authorized Broker, load the Fan-out scenario, pass Preflight, and confirm the expected live traffic.
BEFORE YOU START
Installed app · authorized Broker · exact endpoint
SAFE BASELINE
TRAFFIC
DONE
25 online · 1 send/s · 24 recv/s · 0 errors
Open Bench from the Mqttable sidebar. If the Runtime has no saved Benchmark target, select Benchmark Now.
In New Broker, enter:
First Fan-out;45 seconds;0 seconds;Benchmark Now does not start or provision a Broker. The screenshot uses the disposable documentation target Bench Docs Demo at mqtt://127.0.0.1:18883; do not copy that endpoint unless you already started your own listener there.
Select Test Connection. For this tutorial endpoint, expect both MQTT versions to report Connection OK, then select Create.
The Benchmark Broker test sends no MQTT username or password and uses the configured TLS settings. Authentication refusal is not a save restriction: configure the Benchmark client credentials separately. This page does not provide the standalone Client test action, and a successful endpoint probe does not verify message permissions.
Use your own authorized endpoint; the probe reports each MQTT version separately.
Open the beaker menu and choose Fan-out (1 pub → 1K subs). The template creates:
fanout-pub: one Publisher that sends a QoS 1 message to fo/data every second;fanout-sub: 1,000 Subscribers on fo/#.Do not run the 1K template as loaded. It is an editable scenario, not a safe first-run size.
Load the complete Fan-out plan, then reduce its Subscriber scale before Preflight or Start.
Open fanout-sub and change exactly these two values:
1000 → 24;100 → 24 clients/sec.Save the Group. Leave fo-sub-{index}, MQTT 5.0, Clean Start, and the 300-second Keep Alive unchanged. The template already supplies the matching fo/data Scheduled Message and fo/# Subscription; you do not need to open or recreate them for this first run.
The first-run safety boundary is 24 Subscribers at a target of 24 new connections per second.
Select Run preflight. Before creating load, confirm the summary shows:
fanout-pub and fanout-sub;Use the result as a gate:
The local capture's warnings concern the macOS load generator's mbuf baseline and loopback network path. They did not block this small functional demo, but they would make a Broker capacity comparison unreliable. Resolve host warnings before using a benchmark as performance evidence.
Preflight must describe the workload you intend to run and contain no unresolved Blocker.
With Warm-up set to 0, Start moves from Setup directly into the 45-second Measurement and then Disconnecting.
During Measurement, compare the live cards with the plan:
The relationship between Online, Send Rate, and Recv Rate proves that the baseline is running as configured.
Success: your first Benchmark is now running against your authorized Broker. You can stop here—the five-minute path is complete. Continue only if you want to interpret, export, customize, troubleshoot, or remove it.
After 45 seconds, require Showing last run snapshot · Completed and a Phase Timer of 00:00:45. The live Online, Send Rate, and Recv Rate correctly return to zero after Disconnecting; use the retained charts to judge the finished Measurement.
On Latency:
Completed and the retained charts prove the Measurement finished; zero live rates show teardown completed.
These values describe only this run. A loopback result is not a remote Broker capacity claim. Keep the Broker, network path, Payload, QoS, scale, duration, and load-generator host comparable before comparing two runs.
The completed screenshot shows Stale in the Preflight strip even though the last-run snapshot is Completed. The snapshot remains evidence of this finished run; Preflight must be rerun before another Start.
To keep portable evidence, open Chart actions → Export All Data. Mqttable downloads benchmark_all_charts_data.csv; the formal export contains Measurement rows and excludes Warm-up rows.
Export All Data preserves the completed Measurement outside the live chart.
Change one dimension at a time so the next result remains explainable:
Every configuration change makes the previous Preflight stale. Run it again before Start.
bad_username_or_password, check the Benchmark target credentials and Broker authentication settings. The details remain available after dismissing the notification or refreshing the page, until another run replaces the snapshot or the app exits.fo/data against fo/#.Keep the target if you want to edit and rerun it. To remove it, stop any active run, select the exact Broker identity you created in step 1, then choose Delete in Edit Broker. The screenshot shows the documentation identity Bench Docs Demo; select your own exact name instead.
Delete only the exact tutorial target; this also removes its Groups, Clients, and related Benchmark data.
Capability and safety boundaries:
1–600 seconds of Measurement per run. Pro removes that duration limit; Run Duration = 0 means unlimited Measurement and therefore requires Pro.After this baseline, use Monitor to correlate Runtime resources with Benchmark phases, or Proxy to introduce controlled network faults.