# Questions for system performance metrics broadcasted by OPCUA

**URL:** <https://forum.inductiveautomation.com/t/questions-for-system-performance-metrics-broadcasted-by-opcua/98951>\
**Category:** Ignition\
**Tags:** opcua\
**Created:** [November 21, 2024, 6:19pm UTC](https://forum.inductiveautomation.com/t/questions-for-system-performance-metrics-broadcasted-by-opcua/98951 "2024-11-21T18:19:25Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![face\_plant](https://avatars.discourse-cdn.com/v4/letter/f/e495f1/32.png) [@face\_plant](https://forum.inductiveautomation.com/u/face_plant)\
**Post date:** [November 21, 2024, 6:19pm UTC](https://forum.inductiveautomation.com/t/questions-for-system-performance-metrics-broadcasted-by-opcua/98951/1 "2024-11-21T18:19:25Z")

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Hello! I have found the following tags being broadcasted by ignition's OPCUA server:

- `[System]/Gateway/Performance/CPU Usage`
- `[System]/Gateway/Performance/Disk Utilization`
- `[System]/Gateway/Performance/Memory Usage`
- `[System]/Gateway/Performance/Memory Utilization`

My first question is, are these the correct units for these tags?

- `CPU Usage` =\> % (0.0-1.0)
- `Disk Utilization` =\> % (0.0-1.0)
- `Memory Usage` =\> MB
- `Memory Utilization` =\> % (0.0-1.0)

My second question is, what exactly are these metrics from? A combination of all the ignition processes (java, mmpServer, etc.)?

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**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [November 21, 2024, 6:25pm UTC](https://forum.inductiveautomation.com/t/questions-for-system-performance-metrics-broadcasted-by-opcua/98951/2 "2024-11-21T18:25:52Z")

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As a point of clarification, these don't really have anything to do with OPC UA. These are Ignition system tags, and you happen to have the Exposed Tags feature enabled and be accessing/seeing them over an OPC UA connection.

They are documented here: [System Tags | Ignition User Manual](https://docs.inductiveautomation.com/docs/8.1/platform/tags/types-of-tags/system-tags#performance-system-tags)

CPU usage is [0.0-1.0].

Disk and memory utilization are a ratio of used to max available or something like that.

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<div class="post-metadata">

**Author:** ![face\_plant](https://avatars.discourse-cdn.com/v4/letter/f/e495f1/32.png) [@face\_plant](https://forum.inductiveautomation.com/u/face_plant)\
**Post date:** [November 21, 2024, 6:32pm UTC](https://forum.inductiveautomation.com/t/questions-for-system-performance-metrics-broadcasted-by-opcua/98951/3 "2024-11-21T18:32:02Z")

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I see, thank you for the clarification.

However, I think there might be a issue with the documentation. In the docs linked, it lists Memory usage as in megabytes but I think it might actually be bytes. For example, by ignition instance is currently reporting `176203568` which would be **~176 TB**

Max Memory is also listed as being reported in MB but also seems to actually be reporting as bytes.

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/8/4/84145253a696670ed9d92a7317f9dc9ae12376cb.png)

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<div class="post-metadata">

**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [November 21, 2024, 6:42pm UTC](https://forum.inductiveautomation.com/t/questions-for-system-performance-metrics-broadcasted-by-opcua/98951/4 "2024-11-21T18:42:11Z")

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Yes, I think all the memory units are bytes, not MB. I'll let the docs team know.