xMII Data Processing Limitations

[former_member186262]

Hi

I have a couple of queries concerning the loading capability of xMII .

1. Is there a limit on the number of machines / databases / 3rd party applications that can be hooked on to xMII? OR Whether there is any the effect on system performance as more and more apps are hooked on to xMII?

2. Is there some the data processsing requirement (in terms of bit rate or rate of data feed - which could be very high in a process industry) that needs to be considered for xMII?

Thanks

Deepak Joshi

[sufw · Accepted solution]

Hi Deepak,

We have encountered some issues in xMII 11.5 when processing large XML files whereby Business Logic Services simply stops executing. This may be due to the ServletExec process running out of RAM; while this is configurable, it is limited to 1.5GB in version 11.5.

We have come across situations where the above happens when processing XML files of approx. 12MB, but this most likely depends on the complexity of the BLS transaction being executed...

Hope this helps,

Sascha

[former_member186262 · Accepted solution]

Hi

Thanks a lot for your reply. So basically the 1.5 GB RAM is the limiting factor. Is it possible to expand this RAM?

Also would this also be a limiting factor on the number of interfaces (with say SCADA / DCS etc systems) i can build with xMII?

Thanks

Deepak

[sufw · Accepted solution]

Deepak,

as far as I know, the ServletExec engine which does a lot of the processing in xMII is limited to using a maximum of 1.5GB dedicated memory. So if your server has 4GB of physical RAM, you can dedicate 1.5GB to ServletExec and still have enough to run Windows comfortably.

To my understanding, this limitation is removed in version 12 as it runs on the NetWeaver java stack rather than ServletExec.

How many systems are you looking at connecting to? What sort of load do you expect the system to be under (e.g. in number of messages & size per hour, number of concurrent users, etc.)?

[former_member186262 · Accepted solution]

Hi Sascha

Thanks again for your response.

If i am to assume that i would have 10 users on the xMII installed in a plant (10 interfaces of xMII with the users) and it is connected to machines (SCADA, DCS etc) which record and display data (like say temperature / min, pressure / min, flowrate / min, etc).

Is there any way to tell how may such machine interfaces it would support?

This is a question more from the prespective of sales or pre sales. Many of our clients want multiple equipments connected and we are not sure whether we can do that without hampering the performance of the system.

I understand that 1.5 GB is the limitation in V11.5 so that clubbed with parameters like load expected on the system by in number of messages & size per hour, number of concurrent users, etc. But is there any other way if quantifying this?

This interaction has been extremely helpful. Thanks again

Deepak

[sufw · Accepted solution]

Deepak,

It seeks like you are describing a scenario in which xMII directly connects to very low-level shop floor equipment and systems (e.g. DCS, PLCs?)... I'm not sure I would use xMII for that; I would place it a little 'higher' in the architecture - above MES applications with connections to SCADAs, etc. only by exception.

Ryan, Jeremy, any thoughts?

Sascha

[Former Member · Accepted solution]

I agree with Sascha's last comment.

In more general terms, I think your measures shouldn't be on the number of connections, but how frequent they are used, the amount of data being processed, and what you are doing with the data.

It's easy to imagine one xMII server connected to 10 different systems by 100 users. It's not that uncommon. But, are those users concurrent? And are they all doing SPC analysis on 5 million data points (don't go there please...), and how responsive are the underlying data sources?

I don't know if there is a sizing document or application for xMII or not, other than what is in the help docs. I do think this is a great place to start for recommendations.

Also, the 1.5GB memory limitation is true to my knowledge. Again, in general, I would imagine decent-sized (erring on heavy) is a dual-processor, 4GB memory box. If you are letting the data sources do the work (ie, history vs. history event query for tag, database filtering vs bls filtering, custom bapi vs. a bapi that gets all data and filter via bls), you'll find that this should be <b>plenty</b>of horsepower.

[former_member186262 · Accepted solution]

Thanks a lot Sascha / Ryan

This was very useful. This will surely help in sizing a project.

Thanks again