800xA 5.1 FP4 Load Balancing
Looking at configuring Affinity for load balancing to improve system performance. Is there an easy way to see which nodes are connecting to which AS and CS as of current? I used afwapplogviewer but not sure I am getting the full picture since when I look at the AdvDsOPCConnector statistics, 5 of the connectivity servers are not showing connected anywhere except to the aspect servers. We have 4 redundant pairs of connectivty servers so I would expect to see the pair at least connected to each other.
I compared with another system we have and the other system shows all the connectivity servers connected to their pair plus some.
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The "Connected clients" (top) section of the AppLog OPC DA Connector statistics is an excellent feature to review OPC DA load sharing.
An empty list points to
a) no current demand for this OPC server's items
- or -
b) inappropriate affinity setting (blocking clients)
In my view the main reason to deploy affinity is for system robustness and availability.
Load sharing is pretty good w/o affinity, but the randomization may have caused two or more adjacent workplaces to select the same set of servers which is bad if there is a problem in the server(s), eg a slow memory leak or a faulty harddisk that may render the client group inoperable.
Use affinity to ensure adjacent workplaces select different servers.
Node groups, eg "Even servers", "Odd servers", "Even clients" and "Odd clients" may save a lot of configuring work.
Always put the "All nodes" last on each affinity row to prevent a server to become inaccessible.
Yes there is way to see the node having affinity to which CS and AS.
- Open Service Connection Viewer from PPA Icon in the Windows taskbar.
- Scroll Down to Find "Aspect Directory" and observe the Green trainagle pointing to which node, is having affinity to that Node.
- Simillarly, Drill down to "OPCDA_COnnector"
Hope this will help you.
Thank you for your replies.
Stefan, I am trying to determine if Affinity setup is needed on our system or whether the system is handling it well enough without Affinity configuration. The operators are reporting slow response in bringing up faceplates and switching screens. I have looked at the network as well as performance on the clients themselves and can not find anything there. I am looking for solutions and thought maybe load balancing was an issue. That is when I discovered some connectivity servers not showing connected to any others which I find that hard to believe. I am hesitate to configure Affinity if we have another issue somewhere that maybe this points to. I have attached a document that shows what clients are connected where (hope it makes sense). Do you have any other suggestions?