Aggregating server unable to connect to more than 24 servers

[apetrashyk]

Hi,

I have created an aggregating server/client that needs to connect to more than 70 servers, read data from them and provide access to these data to whoever else connects to it.
The way I'm implementing this is by creating a client object for each connection, and then simply keeping track of which server each client is connected to.

Things are working just as I'd like them to except for when I try to connect to more than 24 servers -- my connections fail with the status code BadResourceUnavailable. According to the documnetation, this happens when an operating system resources is unavaialbe, however, I can't tell which exact resource is unavailable.

Any idea what's going on and how to resolve this?

Thank you,
Andriy


EDIT: The number of maximum connections is actually 25, not 24. Not that it matters, I suppose.

[apetrashyk]

Just to expand on this, the problem persists even if I simply connect to the demo server, the one provided with the SDK, running locally. So with the demo server running on localhost:4840 and the client running on the same machine, I still get the error after 25 connections.

Moreover, simply taking the demo client code and changing it so that on connect it creates many sessions and connects all of them to the server (not just one as in the original demo client), and attempting such a multiple connection to the demo server running on the same machine (localhost:4840), I get the same error after 25 connections.

All of this happens on a Centos 7 machine. Testing on a Centos 6 machine produced identical results.
However, no such error occurs on Ubuntu 17.10.
I also create a database connection in the same client, and I can create really an unlimited number of database connections, but only 25 OpcUa connections. Very strange...

Any ideas on how to resolve this will be greatly appreciated.

Thank you,
Andriy

[Support Team]

Hello Andriy,

I assume that on your CentOS system there are some more restrictive limitations on the resources a process is allowed to use.
First of all you should find out if this error is generated on the client side or on the server side (my guess would be client).
Turn on tracing in your application (UaAppTraceLevel=Data, UaStackTraceLevel=DEBUG). You should find some more detailed information there about what operation went wrong.