VMware Horizon Community
BenFB
Virtuoso
Virtuoso

High CPU usage on UAG

I have three UAG running 3.3.1 that are being load balanced. Recently I've noticed that our UAG are averaging 90% CPU usage and regularly spike to 100% with only 100-140 sessions. The UAG have the standard configuration of 2 vCPU and 4 GB.

The Horizon 7 Configurations Maximums and documentation state that a single UAG can support up to 2,000 sessions.

VMware Horizon 7 sizing limits and recommendations (2150348)

In my search I found this in the documentation.

VMware recommends to use 4 vCPUs and 10GB RAM for Unified Access Gateway appliances to support maximum number of connections when used with Horizon 7.

Horizon Connection Server Maximums and Virtual Machine Configuration

I'm trying to understand if this is normal CPU usage or if we should be concerned and add more resources. It doesn't seem like adding 2 more vCPU and 6 GB of memory would allow for 1,900 more sessions at our current load. I'm tagging markbenson​ since I suspect he is the only one that knows.

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6 Replies
sjesse
Leadership
Leadership

I was asking questions at vmworld and I remember them mentioning the increase as well. We tried loadtesting our enviornment based on the html client and only 80 out of 160 user sessions completed successfully.

I looked  one uag right now and that have 30 users connected through it and its nothing, around 3% average.

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markbenson
VMware Employee
VMware Employee

Make sure UDP 8443 is open on the firewall. CPU utilisation will be higher if UDP 8443 is blocked.

BenFB
Virtuoso
Virtuoso

We were trying to avoid using UDP 8443 and pushing everything over TCP/UDP 443 but discovered that's not possible. I'll revisit moving the traffic back to UDP 8443.

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BenFB
Virtuoso
Virtuoso

markbenson

In the interim could we simply increase the UAG from 2 to 4 vCPU?  Would shifting traffic from TCP 443 to TCP 8443 help or is this strictly the overhead from TCP vs. UDP?

My understanding from other conversations we've had is that UDP 443/8443 is only used when their are network issues like packet loss and latency.

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BenFB
Virtuoso
Virtuoso

Just following up to see if markbenson​​ or anyone else can weigh in.

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