Canary Administrator – Diagnostic Health System enabled but health tags not updating
The Diagnostic Health System is enabled in the Store And Forward settings (Admin → Store And Forward → Settings), with a frequency of 1 minute and destination set to localhost. However, health tags are not receiving historical updates — most, if not all, have been stale since their creation on 07-Apr-2025.
Evidence from the Canary Administrator UI (screenshots attached):
- Screenshot 1 (Settings): The Diagnostic Health System is enabled (
Is Enabled: checked), withFrequency: 0d 0h 1m 0s 0ms,Destination Historians: localhost, andHistorian Writers Target: 0. - Screenshot 2 (Streams): The Diagnostic Health System stream appears at the top of the list with 255 tags, but shows
INPUT/SEC: 0andOUTPUT/SEC: 0, meaning no data is flowing through the health pipeline despite the system being active.
Evidence from the API (tag export attached):
We are reading the full Canary health tag tree via API under the following structure:
Canary/Reading— 8 tags (Live/History requests, TVQs, max latency, client count)Canary/Writing— 6 tags (TVQs, requests, inserted TVQs, tag handles, client count)Canary/Views— 14 tags (API call count, CPU, memory, Axiom metrics, thread count)Canary/Health— 39 tags across subfolders: root-level metrics (Version, Sys_Up_Time, Memory_Usage, CPU, Services), MQTTCollector, Store_And_Forward, Views, Historian, Axiom, and Drives (C/D)Canary/System— 10 tags (CPU usage, memory, historian working set, handle count)Canary/VIO— 6 tags (write/file open count, avg/max latency)
All tags return current live values via the API (e.g., Sys_Up_Time: 1,456,621, Memory_Usage_perc: 59.6%, Store_And_Forward.Stream_Count: 35), confirming the Diagnostic Health System is generating data internally. However, none of these tags have historical data recorded in the historian — values have not changed since their initial creation on 07-Apr-2025.
This suggests that the health data is being computed and exposed for live reads, but is not being written/historized to any dataset.
Questions:
- Is there an additional configuration step required for the Diagnostic Health System to write historical data (e.g.,
Historian Writers Targetis currently set to0in the settings — should this be non-zero)? - Does the Diagnostic Health System require a dedicated dataset to be created before it can historize data?
- Are there specific service-level prerequisites or permissions that must be in place for the health tags to flow through Store And Forward into the historian?
Expected behavior: With the Diagnostic Health System enabled at a 1-minute frequency and destination set to localhost, all health tags should be historized at the configured interval, not just available as live values.


2 replies
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Hi ,
The Diagnostic Health System received updates in version 26.1. If you're monitoring tag values that haven't received an update since April 7th, there's a good chance those tags have been renamed to something else or removed if you've recently upgraded the software.
The Historian Writers Target should eventually display a number after an hour of runtime. All DHS tags are written to the {Diagnostics} dataset.
