Alibaba Cloud Content Delivery Network (CDN) is a suitable product for the following scenarios: (Number of correct answers: 2)

• A. News websites with more than 30 million daily page views and users are all from Singapore.
• B. Images, HTML, CSS and JS files on a medium-sized E-commerce website.
• C. BBS forums with less than 100 daily page views.
• D. Static sites with more than 100,000 daily page views.

During the process of backing up an RDS database, a developer found that the backup failed. What might cause this to happen?

• A. DDL operations were performed during the backup
• B. DCL operations were performed during the backup
• C. DML operations were performed during the backup
• D. The database instance is not stopped

Which of the following descriptions of Alibaba Cloud ECS storage are correct? (Number of correct answers:
3)

• A. Two types of Cloud Disks can be attached to an ECS: System Disks and Data Disks. System Disks host the ECS instances operating system.
• B. Alibaba Cloud provides a wealth of block storage products for ECS, including Cloud Disks (virtualized storage) and Local Disks (physically attached to the server(s) that host your ECS Instances).
• C. Both Local Disks and Cloud Disks use a multi-copy distributed storage mechanism, which has low latency, high performance, durability, and high reliability, and supports creation, expansion and release at any time.
• D. Cloud Disks come In several different varieties: ESSD (Enhanced Solid State) Cloud Disks. SSD (Solid State ) Cloud Disks, and high-efficiency Cloud Disks.

When using Alibaba Cloud CDN, a visitor's request will first be routed to a CDN edge node, and in the event of a cache miss at this edge node, the node will fetch data from the origin site (back-to-source request). Even with this redirection, it is possible for the origin site to see the visitors real IP address. Which of the following statements about obtaining the visitor's real IP address are correct? (Number of correct answers: 2)

• A. You can activate the "record visitor's real IP" function in the Alibaba Cloud CDN console, then you can directly view visitor's IP addresses from the Alibaba Cloud CDN access logs.
• B. A visitor's real IP address is stored in the "X-Forwarded-For" HTTP header It can be directly obtained via Apache or NGINX logs.
• C. In Windows, if IIS is used, after installing the "F5XForwardedFor" extension module, the visitor's real IP address can be seen via IIS logs.
• D. A visitor's real IP address can only be obtained by modifying the site or web application.

Which of the following options is correct, regarding Object ACL in Alibaba Cloud's Object Storage Service (OSS)?

• A. If the permissions of an object are not set, the permissions of the object are inherited from the bucket.
• B. Object ACL is an object-level (not bucket level) permission control mechanism. There are currently three levels of access rights: private, public-read, and public-read-write.
• C. You can set the ACL associated with an object by examining the X-OSS-Object-ACL header in the HEAD request, when making the PutObjectACL API call.
• D. "Private" indicates that an object is a private resource, that is, only the owner of the object has read and write permissions on the object, and other users can read but have no permission to modify or delete the object.