Alibaba ACA-Cloud1 Exam - Topic 1 Question 91 Discussion

Actual exam question for Alibaba's ACA-Cloud1 exam

Question #: 91
Topic #: 1

When using Alibaba Cloud SLB, you can set different weights for backend ECS instances. The higher the weight of a backend ECS instance, the more load will be assigned to it. If an SLB instance has 5 ECS instances in the backend server pool, all of which are healthy. Among these 5 ECS instances, the weight of ecs_inst1 is set to 100. Which of the following statements is correct?

AWe do not know the weight settings of the remaining 4 ECS instances, so we cannot tell what would happen.

B100% of loads will be assigned to ecs_inst1, and the rest 4 ECS instances will stay idle.

CBased on SLB's working mechanism, approximately 20% of loads will be assigned to ecs_inst1.

DBased on request level parameters of external requests, all requests with a request level parameter of 100 will be transferred to ecs_inst1.

Show Suggested Answer

Suggested Answer: A

Alibaba Cloud Server Load Balancer (SLB) is a service that distributes network traffic across multiple ECS instances to improve the service capabilities of applications. SLB supports different load balancing algorithms, such as round robin, weighted round robin, and least connections. When using the weighted round robin algorithm, SLB assigns different weights to backend ECS instances based on their processing capabilities. The higher the weight of a backend ECS instance, the more requests it will receive from SLB. However, the weight of a backend ECS instance is not the only factor that determines the load distribution. The number and the weight of other backend ECS instances in the same server group also affect the load balancing result. Therefore, without knowing the weight settings of the remaining 4 ECS instances, we cannot tell what would happen to the load distribution among the 5 ECS instances. The other statements are incorrect because they assume a fixed or proportional load distribution based on the weight of ecs_inst1, which is not necessarily true.

Alibaba Cloud Server Load Balancer

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by King at Aug 03, 2025, 11:52 PM

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Loreta

2 months ago

Wait, so only one instance can get all the load? That’s surprising!

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France

2 months ago

Definitely not B, that’s way too extreme!

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Bev

3 months ago

D seems a bit off, isn't it?

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Ardella

3 months ago

C sounds about right, but I'm not 100% sure.

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German

3 months ago

I think we need to know the weights of the other instances to decide.

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Delmy

3 months ago

I don't think all requests would go to ecs_inst1 just because it has a weight of 100; that seems too extreme.

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Kathrine

4 months ago

I feel like option C makes sense since it says "approximately," but I can't recall the exact distribution method used by SLB.

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Micaela

4 months ago

I think I practiced a question like this, and it mentioned that the total weight matters, so it can't just be 100% for one instance.

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Hyun

4 months ago

I remember that the weight determines how much traffic each ECS instance gets, but I'm not sure how the other weights affect ecs_inst1.

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Lettie

4 months ago

Ah, I see what's going on here. The key is that the question states the weight of ecs_inst1 is set to 100, but doesn't give the weights of the other 4 instances. Since the weights are relative, that means ecs_inst1 will get 100% of the load, and the other 4 instances will be idle. Option B is the correct answer.

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Lovetta

4 months ago

Hmm, this is a tricky one. If ecs_inst1 has a weight of 100, and the other 4 instances' weights are unknown, then I don't think we can definitively say how the load will be distributed. The question doesn't provide enough information to determine the exact load distribution. I'll have to go with option A.

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Rebbecca

5 months ago

Okay, let me try to break this down. Since ecs_inst1 has a weight of 100, and the other 4 instances' weights are not specified, I'm guessing that the load will be distributed proportionally based on the weights. So ecs_inst1 should get around 20% of the total load, while the other 4 instances will each get a smaller share. I'll go with option C.

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Carin

5 months ago

I'm not entirely sure about this one. The question mentions that the weight of ecs_inst1 is set to 100, but it doesn't give any information about the weights of the other 4 instances. I'll need to think carefully about how the SLB load balancing mechanism works to determine the correct answer.

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Delfina

5 months ago

Haha, I bet option D was written by someone who's never actually used SLB before. 'Request level parameters'? Really? Option C is clearly the way to go.

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Jaclyn

5 months ago

I'm going with option B. If one instance has a weight of 100 and the others are unknown, it makes sense that 100% of the load would be assigned to that instance.

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Alease

5 months ago

Hmm, I think option C is the correct answer. SLB's load balancing algorithm will distribute the traffic based on the weights, so with ecs_inst1 having a weight of 100, it should get around 20% of the traffic.

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