Why should disk queue length above zero be used to identify bottlenecks?

Why should memory consumption above 90% be used to identify bottlenecks?

Why should CPU consumption above 85% be used to identify bottlenecks?

How can the architect identify if the server OS machines are the source of a bottleneck?

How can the architect identify if the Provisioning Services servers are the source of a bottleneck?

How can the architect identify if the Delivery Controller is the source of a bottleneck?

Scenario: The architect for the company has identified that virtualizing the entire server infrastructure will provide the best return on investment (ROI) and lowest
maintenance costs for the new infrastructure. In order to proceed with this recommendation, a monitoring strategy must be put in place to ensure that the
virtualization platform does NOT become overloaded.
How can the architect identify if the XenServer hosts are the source of a bottleneck?

Scenario: The architect for the company has identified that virtualizing the entire server infrastructure will provide the best return on investment (ROI) and lowest
maintenance costs for the new infrastructure. In order to proceed with this recommendation, a monitoring strategy must be put in place to ensure that the
virtualization platform does NOT become overloaded.
Which virtualization component should an architect monitor to identify virtual desktop bottlenecks?

Scenario: The company needs to ensure that the provisioning traffic does NOT interfere with the exisiting PXE solution. The Provisioning Services servers will be
connected to a 10 Gbps network.
How does using NetScaler App Firewall help the company secure streaming traffic?

Scenario: The company needs to ensure that the provisioning traffic does NOT interfere with the exisiting PXE solution. The Provisioning Services servers will be
connected to a 10 Gbps network.
How does using a dedicated switch help the company secure streaming traffic?