topic Re: Ram only being consumed on one engine in Management & Governance

Ram only being consumed on one engine

Anonymous — Fri, 18 May 2018 15:17:29 GMT

I have a multi node engine set up with 4 engine nodes, 1 central, 3 proxy, 1 scheduler.

I notice moderate to low CPU usage across all engine nodes but high ram usage on only one of them.

I can't imagine this is typical behavior. We have an application with massive RAM footprint we need to spread across nodes.

The load balancing is being done with DataPower, an IBM product.

Andrew

Re: Ram only being consumed on one engine

Levi_Turner — Sat, 19 May 2018 11:03:07 GMT

Hey Andrew,

What is the Virtual Proxy > Load Balancing for the Proxy/Proxies that end users access?

Re: Ram only being consumed on one engine

Anonymous — Mon, 21 May 2018 14:21:15 GMT

That is managed by an IBM Data power server, this is the load balancing rule for that server.

Re: Ram only being consumed on one engine

Levi_Turner — Mon, 21 May 2018 23:48:17 GMT

So that's one element. At described you have:

User > Proxies
Proxies (and their Virtual Proxy/Proxies) > Engines

(1) is handled by the network appliance, but I am asking about (2). So under Virtual Proxies > Load Balancing what Engine(s) are selected across the Virtual Proxies at play?

Re: Ram only being consumed on one engine

Anonymous — Tue, 22 May 2018 14:18:54 GMT

Hey Levi,

my initial post was found to be wrong, Ram only appears to be consumed on one engine but inspecting the line further, they all are maxed out. Proxies (and their Virtual Proxy/Proxies) > Engines

Under Proxies > Engines, all engine nodes are listed. So basically any engine can serve up any application at a given time, like the default behavior. We are just experiencing performance issues likely due to cache warming issues duplicating the ram footprint.

Re: Ram only being consumed on one engine

Levi_Turner — Tue, 22 May 2018 17:38:20 GMT

Ahh. So architecturally the key thing to keep in mind is that Load Balancing in Qlik Sense at current is pure round robin. Practically if you know you have a massive app, you would likely want to pin that app to 1 engine using Load Balancing Rules and distribute the rest to the others (or all apps but big app to all front end engines and big app to just 1 front end engine).