Decrease AC450 high load
AC450 high load
I have a redundant MB300 network consisting of 3 controllers ,2 of them are AC450 (Named ACA and ACB) , 1 SafeGuard 415 and 10 Operating Stations OS500 working under Unix .
The Controller ACA load is 55% (with a frequent spikes which reach 75%) and ACB load is 25% (with No Spikes). So my problem is how to decrease the load of ACA and decrease the Frequent Spikes in the Load?
So by check, I found that controller ACA Task Load DCTA200 (TTD Primary memory logging) is changing between 7 to 11% and DCTA500 (TTD Manipulation) is changing between 0 to 7% and DCTA600 (TTD Subscription) is changing between 2 to 4%.
So how can I decrease the load of the trend without deleting any trend?
Also I need to know the meaning Of TTD manipulation and TTD subscription which may help me in decreasing the load.
The load dissipated by DCTAx00 is caused by TTD logging and HMI access to those logs.
The spikes are a natural behaviour. TTD tasks run with low priority and will not interfer with the controller's normal duties. In fact, "holes" in TTD trends is often debated at support - given the low prio, it is one of the things the controller will "drop" first if challenged by something else.
Only method to remove the spikes caused by DCTAx00 is to delete the logs.
55% average CPU load with "TTD-spikes" up to 75% is very far from overload - the Advant Controller 400 is very robust, even at 90% CPU load.
I would try other cleaning before chasing down TTD logs, eg unresolved symbols in OS500 stations (due to incorrect references in process displays) causing background load in CXNM200.
Replacing SC510 with SC520 carrier board will (if not already in place) more or less remove all load from CXNxxx (network tasks) off the main CPU.
A load of 75% CPU in an AC400 series controller is NOT high.
Spikes like this caused by TTD logging are absolutely normal. The DCTA tasks are a lower priority than the PC program interpreters and will timeout long before controller functions are affected.
Theres nothing wrong in what you describe - in fact your CPU load is quite low. The AC400 controller series can run at 80 - 90 % average CPU load with short spikes to 100% caused by TTD logging quite happily.