Alibaba Cloud Object Storage Service (OSS) is ideal for storing large amounts of unstructured data, such as images and videos. By migrating static files to OSS, you can free up disk space on your ECS instance, allowing you to efficiently handle storage needs as your business scales. OSS is a highly scalable and cost-effective solution for handling media files and other static assets.

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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. However, the load distribution is not based on the absolute value of the weight, but on the proportion of the weight in the total weight of all healthy backend ECS instances. For example, if there are two healthy backend ECS instances with weights of 100 and 200 respectively, the first instance will receive 33.3% of the load, and the second instance will receive 66.7% of the load. Therefore, to determine the load distribution of the 5 ECS instances in the question, we need to know the weight settings of the remaining 4 ECS instances. Without this information, we cannot tell what would happen. The other options are incorrect because they are based on wrong assumptions or misunderstandings of the SLB weight setting mechanism. 

OSS does not use a hierarchical structure for objects, but instead uses a flat structure. All elements are stored as objects in buckets. To use OSS in the same manner in which local file systems are used, you can configure Cloud Storage Gateway (CSG).

https://www.alibabacloud.c om/help/doc-detail/31817.htm

 The statement C is correct, because in an OSS bucket, all elements are stored as objects. An object is the basic unit of OSS storage. Each object consists of a unique key, data, and metadata. The key is the name of the object, which is used to identify the object in a bucket. The data is the content of the object, which can be any type of file, such as text, image, video, or audio. The metadata is the information about the object, such as its size, type, creation time, and custom attributes.  References : =  Object Storage Service:Overview - Alibaba Cloud

Alibaba Cloud CDN requires a domain name to function, as it uses DNS resolution to direct requests to the nearest edge nodes. CDN cannot directly accelerate an IP address without a domain name, so the statement is false.

The X-Forwarded-For field in HTTP header is used to identify the originating IP address of a client connecting to a web server through an HTTP proxy or a load balancer. When the “Obtain the Visitor’s Real IP Address” function is enabled in Alibaba Cloud SLB, the SLB instance adds the X-Forwarded-For field to the HTTP header of each request and forwards the request to the backend server.  The backend server can then obtain the real IP address of the visitor from the X-Forwarded-For field 1 . The format of the X-Forwarded-For field is as follows:

X-Forwarded-For: client, proxy1, proxy2

where the value is a comma+space separated list of IP addresses, the left-most being the original client, and each successive proxy that passed the request adding the IP address where it received the request from.  In this example, the request passed through proxy1, proxy2, and then the SLB instance (proxy3). 2

References:   Obtain client IP addresses - Server Load Balancer - Alibaba Cloud ,  X-Forwarded-For - MDN Web Docs

Auto Scaling in Alibaba Cloud is designed to automatically adjust resources, such as ECS instances, based on the demand and scaling policies. This works best with applications that are stateless and horizontally scalable, as these applications do not rely on data stored locally on an instance, allowing them to scale in and out without affecting performance or user experience. Statelessness and horizontal scalability allow Auto Scaling to manage ECS instances efficiently without manual intervention.

Intelligent DNS resolution is a feature of Alibaba Cloud DNS that allows users to configure different IP addresses for the same domain name based on the geographic locations or ISPs of the visitors. This way, visitors can access the nearest or optimal server for better performance and availability. Intelligent DNS resolution does not support web page content caching, which is a function of Alibaba Cloud CDN. Alibaba Cloud CDN is a distributed network that delivers content from the origin server to the edge nodes closest to the end users, reducing the network latency and bandwidth consumption. Alibaba Cloud CDN caches the static content of the web pages, such as images, CSS, and JavaScript files, on the edge nodes, so that the users can access them faster and reduce the load on the origin server. A user will receive data from the cache in the first-time access, and then will be updated from the origin site in subsequent requests based on the cache expiration time.

References :

1 : Intelligent DNS resolution - Alibaba Cloud DNS - Alibaba Cloud Documentation Center

4 : Alibaba Cloud Content Delivery Network (CDN) performs content acceleration with the support of intelligent DNS resolution The following function_________is NOT included in intelligent DNS resolution.

5 : Alibaba Cloud DNS:Alibaba Cloud line for intelligent DNS resolution (September 16, 2020) - Alibaba Cloud Documentation Center

This is a correct description of distributed computing, where a large task is divided into smaller tasks, distributed across multiple nodes, and later recombined to produce the final result. Distributed computing is widely used to handle large-scale computations and improve processing efficiency.

Alibaba Cloud SLB’s " Rewrite Cookie " mode allows selective session persistence for specific subdomains by setting and rewriting cookies as specified. For example, you can enable session persistence on vip.a.com while leaving img.a.com without it. SLB uses the rewritten cookie to direct subsequent requests to the previously assigned backend server.

Zones in the same region support low-latency intranet communication, ideal for high- availability deployments with inter-Zone fault isolation. Placement of ECS instances in the same or different Zones depends on the disaster recovery and latency needs of the application.

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