Hi,
I've recently received the question from a customer:
If I have a DMS with 2500 elements distributed in 7 DMA, how many DMA should I need to create a replicated DMS?
This is assuming that a replicated element does not have the same resource load in a DMA as a polling element.
The idea is to avoid double polling the elements and to present them in a different surveyor layout than in the original DMS.
Hi Arturo,
There is of course the licensing side of things, but let's assume you got this covered and this is purely a resource load question.
A replicated element will have a bit less load on the DMA, but the difference won't be that spectacular I believe. You win something on the polling, but there is a lot that remains...
A replicated element still needs to be fully loaded in memory with all the parameters and their values. It will still generate the same amount of alarms and trending if you apply the same templates. And other modules like automation, correlation, etc will still do the same.
Also the protocol needs to be fully loaded. It just doesn't need to continuously poll the data source, but it will be notified of the changes. So the data retrieval will be very efficient, but that is only a part of the load.
You should of course also look at the load you have on the current system. Processes like SLElement will have the same load. Only SLProtocol will reduce a bit, and SLPort/SLSNMPManager will drop to zero, but there could be an increase on SLNet. Now you have on average 357 elements per DMA, if you have still some margin on the current system, you could maybe go to 500 elements per DMA.
In any case, I would also like to add that my advice would be to not overload DMAs. I rather see more DMAs with lower specs and fewer element, compared to huge, heavy DMAs with super specs and many elements on there. I also want to keep swarming in the back of my mind!
If you go for a subscription, the number of DMAs don't matter, and if you need e.g. 20 vCPUs to manage those elements, you can spread them over 2 VMs or 5 VMs for about the same price. I would go for 5 DMAs!
Don't hesitate to reach out if you want to discuss this in more detail.
Bert
Good question – if I recall correctly, "how many" will depend specifically on the licensed capacity in the destination DMS: the destination DMA will just host the replicated elements – resource wise, in destination DMA, you still need to account for sufficient horsepower – subscribing to understand a bit more on this aspect