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In this chapter, we specifically explain how to design a highly available framework under the Window server.
Our frame design uses the Window version of the server design:
The overall frame diagram is as follows,
Why do we need to design this way?
This article only briefly describes the pros and cons of NLB and ARR. More technical articles will be released later.
We Introducing NLB, compared to ARR, ARR is an application-level load balancing solution, ARR can only be used as a request entry distribution service, and NLB is a server-level load balancing solution strong>.
If we combine these two Microsoft solutions, we can build a highly available website solution.
The evolution of Application Request Route and NLB high-availability solutions
1. Application Request Route solution, as shown below
< strong>Disadvantages:
ARR can detect whether your iis application is available, and implement a load balancing scheme for user requests. According to the load balancing algorithm we configured, users’ requests are distributed to Application server.
However, if our ARR server is down, our entire application will be unavailable, and it will not meet the high availability requirement of 24*7 use without downtime.
2, NLB’s network load balancing solution
Disadvantages:
NLB can configure up to 32 servers, These 32 servers share a virtual IP in addition to their own independent IP. The user accesses the virtual IP. The nlb cluster determines which application server to distribute the user’s request to according to the configured load algorithm. If an NLB server is down If it is dropped, it will not affect the distribution of messages. It can reach a high-availability solution that does not shut down the machine for 7*24 hours.
However, NLB cannot detect whether your IIS website is down. It can only detect whether the server is down. In this way, if your IIS website has been stopped, nlb will return the request to users. Trouble is coming.
So how do we use Microsoft’s technology to achieve high availability of the website? Yes, it is NLB+Application Request Route .
3, NLB+Application Request Route plan
Advantages: The user requests a virtual ip and connects to nlb , Nlb detects an available server and forwards the request to arr, and arr detects the available website and dispatches the user request to form a high-availability solution.
In the pre-research of frame design, the inspiration source reference: https://cnblogs.com/knowledgesea/p/5157565.html
After a comprehensive analysis, we finally adopted the combination of NLB+ARR to form the following design drawing
For the design of this framework (pros and cons), Yuanfang, what do you think? Welcome to scan the QR code at the top right, follow the official account, and leave a message to complain.