ACP-Cloud1 Sample Questions Answers

The maximum number of connections to an RDS instance primarily depends on the memory size of the instance. Higher memory capacity allows for more simultaneous connections, as memory is a key resource in managing and maintaining connections. Alibaba Cloud RDS scales the connection limit based on the instance's memory allocation to ensure stable database performance.

ECS instance monitoring provides a process monitoring feature that allows you to check the status of specific processes, such as a Python process, and set alerts for automatic notifications if the process terminates unexpectedly. This method is quicker and more efficient than writing a custom script or manually logging in to the console.

SQL injection attacks primarily target databases by exploiting vulnerabilities in web applications. Attackers manipulate SQL queries to gain unauthorized access to the application's backend database, which may lead to data leakage or destruction. Although SQL injection affects the data stored in databases and not directly files or images on the server, the primary target remains the application layer through which the attack is conducted.

To enable Internet access for ECS instances in a VPC, Alibaba Cloud users can use a public SLB with an Internet IP address (Option B) or an SLB with an Elastic IP (EIP) attached (Option C). Both methods allow the SLB instance to receive external requests and forward them to ECS instances within the VPC. Option A is incorrect because it would require a more complex setup without direct Internet access. Option D is incorrect as SLB does not support directly mounting servers from an on-premises data center.

Even though the scaling rule is set to "Adjust to 10 ECS instances," the maximum instance limit set for the scaling group is 8. Thus, when the scheduled task is triggered, Auto Scaling will increase the number of instances up to the maximum allowed, which is 8. Therefore, the scaling group will contain 8 instances, not 10, as it adheres to the defined maximum limit.

Alibaba Cloud provides comprehensive security protection covering networks, hosts, applications, databases, and content for on-cloud clients, but users still need to pay attention to security protection issues. Alibaba Cloud and its customers are jointly responsible for the security of customers’ applications built on Alibaba Cloud. With security responsibilities shared between Alibaba Cloud and its customers, Alibaba Cloud provides a secure infrastructure to decrease the enterprise security burden of customers. As such, customers can configure and use cloud products in a secure manner, thus relieving much of the underlying security burdens while allowing customers to focus more on their core business needs. However, customers still need to follow the best practices and guidelines for cloud security, such as using strong passwords, enabling multi-factor authentication, encrypting sensitive data, applying security patches, etc. Customers also need to monitor and manage the security risks and incidents of their cloud environment using Alibaba Cloud’s security products and services, such as Security Center, ActionTrail, Cloud Firewall, etc. References: Cloud Security- Alibaba Cloud, Security & Compliance Center, Shared Responsibility

 Cloud Firewall is a service that provides centralized protection for your cloud assets and prevents unauthorized access to your servers. Cloud Firewall can monitor and control the inbound and outbound traffic of your servers, and block malicious requests and attacks. Cloud Firewall can also detect and prevent brute force password cracking attempts by using intelligent algorithms and threat intelligence. Therefore, option A is the correct answer. References: What is Cloud Firewall?, Protect servers from brute force attacks

 You do not need to activate and purchase Alibaba Cloud CloudMonitor service to monitor the status of the ECS instance via Alibaba Cloud console. CloudMonitor is a service that monitors Alibaba Cloud resources and Internet applications. CloudMonitor provides a one-stop, out-of-the-box, and enterprise-class monitoring solution1. CloudMonitor collects monitor metrics of Alibaba Cloud resources and custom metrics and enables you to view and understand the usage of the cloud resources, and the health of your business2. CloudMonitor allows you to monitor the metrics of Alibaba Cloud services, detect the availability of websites hosted on ECS instances or carrier servers, and configure alert rules for specified metrics3. However, CloudMonitor is not a prerequisite for monitoring the status of the ECS instance via Alibaba Cloud console. You can monitor the status of the ECS instance via Alibaba Cloud console without activating and purchasing CloudMonitor service. You can view the basic information, configuration, security group, and tags of the ECS instance in the console. You can also view the CPU, memory, disk, and network usage of the ECS instance in the console. You can also use the Cloud Assistant feature to run commands on the ECS instance remotely4. 

Alibaba Cloud OSS is designed for scalable and secure object storage, allowing users to upload and download files through multiple interfaces, including the web console and APIs, offering flexibility and ease of use for developers and administrators.

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Alibaba Cloud RDS automatically deploys instances in master-slave mode (high availability) without additional configuration or charges. This ensures data redundancy and disaster recovery by maintaining synchronous data replication from the master to the slave instance.

 According to the Alibaba Cloud VPC documentation1, a virtual private cloud (VPC) is a virtual network dedicated to your Alibaba Cloud account. You have full control over your VPC, such as specifying the CIDR block, configuring route tables and gateways, and creating subnets. A VPC is an isolated network environment that provides security and flexibility for your cloud computing resources. You can use a VPC to build a secure and isolated network environment on Alibaba Cloud, design your network topology, and specify intranet IP addresses or CIDR blocks in this network environment as needed. Therefore, option B is the correct choice for your scenario. References: What is a VPC? and Alibaba Cloud Virtual Private Cloud.

A. Management and maintenance: To prevent emergent service termination, users need to know the underlying detail like how the data is archived in the resource pool. This is incorrect because cloud storage is designed to abstract the underlying details of how the data is stored and managed from the users. Users do not need to worry about the hardware, software, or network issues that may affect the data availability or reliability. The cloud storage provider is responsible for maintaining and managing the storage infrastructure and ensuring the service continuity1.

B. Service on demand Cloud storage has a huge resources pool, users can apply for and use the resources on demand. This is correct because cloud storage is based on the cloud computing model of service on demand, which means that users can request and access the storage resources as needed, without having to purchase or provision them in advance. Cloud storage providers offer flexible pricing models that allow users to pay only for the storage they use2.

C. High reliability and availability: Provides very high reliability and availability through technologies like 3 redundant copies, automatic failure recovery, etc. This is correct because cloud storage uses various technologies and methods to ensure that the data stored in the cloud is always accessible and durable. For example, cloud storage providers typically replicate the data across multiple servers, regions, or zones to prevent data loss due to hardware failure, natural disaster, or human error. Cloud storage providers also use automatic failure recovery mechanisms to detect and repair any issues that may affect the data integrity or availability3.

D. Ultra-large scale: Data storage can reach TB or even PB level. This is correct because cloud storage can handle massive amounts of data, ranging from terabytes (TB) to petabytes (PB) or even exabytes (EB). Cloud storage providers have the infrastructure and expertise to scale up the storage capacity and performance to meet the growing data needs of users. Cloud storage can support various types of data, such as structured, unstructured, or semi-structured data, and various use cases, such as data backup, data archiving, data analytics, or data sharing.

E. Transparent service: Provides the service through a single SDK. This is incorrect because cloud storage is not a transparent service, but a service that requires users to interact with it through a specific interface or protocol. Cloud storage providers usually offer different types of storage services, such as object storage, block storage, or file storage, each with its own characteristics and features. Users need to choose the appropriate storage service for their data and use the corresponding software development kit (SDK), application programming interface (API), or command-line interface (CLI) to access and manipulate the data.

F. High scalability Storage capacity can be dynamically scaled to meet the needs. This is correct because cloud storage is highly scalable, meaning that users can increase or decrease the storage capacity according to their data needs. Cloud storage providers offer elastic storage services that can automatically adjust the storage resources based on the demand, without requiring users to manually provision or deprovision them. Cloud storage also allows users to scale the storage performance, such as throughput, latency, or bandwidth, to optimize the data access and transfer.

References: 1: What is Cloud Storage? - Cloud Storage Explained - AWS 2: What is Cloud Storage & How Does it Work? | Google Cloud 3: Cloud Storage Reliability and Availability | Cloud Storage Documentation : What is Cloud Storage? - Definition from Techopedia : Cloud Storage Types: Object, Block, and File | IBM : Cloud Storage Scalability | Cloud Storage Documentation

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

 When the scheduled task is activated once, 4 ECS instances will be added in the scaling group. This is because the scaling rule “Add 6 ECS instances” will increase the number of instances in the scaling group to 9, which exceeds the maximum number of instances (7) that is set for the scaling group. Therefore, Auto Scaling will only add 4 ECS instances to reach the maximum number of instances. The remaining 2 ECS instances will not be added to avoid exceeding the quota. 

Alibaba Cloud OSS automatically maintains three copies of each data object to ensure data reliability and redundancy. This setup allows OSS to recover data automatically without human intervention in case of hardware or system failures, ensuring high data durability.

Auto Scaling in Alibaba Cloud supports event-triggered tasks based on CPU workload, memory utilization rate, inbound and outbound traffic, and Disk IOPS as key metrics for scaling decisions. Average system workload (option C) is not a directly supported metric, making options A, B, D, and E correct. These metrics allow Auto Scaling to respond to real-time performance needs.

After stopping an Alibaba Cloud Elastic Compute Service (ECS) instance, you will not be charged for the instance usage fee or the public bandwidth fee (if applicable) until you start the instance again. However, you will still be charged for the disk usage fee and the snapshot usage fee (if applicable) regardless of which region the instance is located in. This is because the disks and snapshots are still occupying the storage space and need to be billed accordingly. Therefore, the statement is false. References: 1 - Billing FAQ - Alibaba Cloud Document Center - What fees do I need to pay after I stop a Pay-As-You-Go instance?

 Alibaba Cloud CDN can record the real IP address of a visitor in the HTTP header field X-Forwarded-For, which can be obtained by the origin server or the user-defined log of Apache and Nginx. Alibaba Cloud CDN also provides a one-click function to enable the recording of the visitor’s real IP address in the console, which can be viewed in the access log. References:

Obtain the real IP address of a client from the origin server - Dynamic Content Delivery Network - Alibaba Cloud Documentation Center1

Welcome to Alibaba Cloud and find out more detail about cdn real ip2

 A read-only RDS instance is a replica of the primary RDS instance that can handle read requests and increase the read capability of the database system. A read-only RDS instance inherits the network type (intranet or internet) of the primary RDS instance and cannot switch between them. Therefore, option D is the correct answer. References: Create a read-only ApsaraDB RDS for MySQL instance, Instance types for read-only ApsaraDB RDS instances

To prevent frequent alerts when User A logs in from Shanghai, the best solution is to configure the Security Center to recognize Shanghai as a frequent login location. This will prevent unnecessary security alerts each time User A accesses the server from this location.

In Alibaba Cloud RDS, read-only instances are synchronized from the master instance but do not allow actions such as creating or deleting databases, configuring backup policies, or changing account authorizations. However, you can configure the read-only instance’s whitelist to control access.

 To execute a task at a specific time such as removing 1 ECS instance every night at 00:00, you need to perform two operations: create a scaling rule and create a scheduled task. A scaling rule is a set of instructions that defines how Auto Scaling scales computing resources in response to changes in business load. A scheduled task is a type of scaling task that can execute a specified scaling rule at a specified time. By creating a scaling rule that removes 1 ECS instance from the scaling group, and creating a scheduled task that executes this scaling rule every night at 00:00, you can achieve the desired result. You do not need to create a new scaling group, because you already have one scaling group created. You also do not need to create an event-triggered task, because this type of scaling task is triggered by events such as Cloud Monitor alarms or API calls, not by a specific time. References: 1, 2, and 3.

According to the Alibaba Cloud Academy, a VPC is an isolated network environment that is completely isolated from each other. Each VPC has an independent tunnel ID, and a tunnel ID corresponds to a virtualized network. This means that different VPCs cannot communicate with each other through the tunnel ID. Subnets are not divided like the traditional network environment, but rather are logical divisions of the VPC. Different cloud servers within each subnet are connected by the same router, but different subnets are interconnected by route tables, not switches. ECS instances in a VPC use security group firewalls for Layer 4 network access control, not Layer 2. The internal networks of different VPCs are completely isolated and can be interconnected through IP addresses mapped to the outside, such as NAT Gateway or EIP. References: ACP Cloud Computing Certification Preparation Course - Internetworking with VPC, Alibaba Cloud VPC User Guide

 According to the Alibaba Cloud SLB documentation1, SLB provides a health check feature that monitors the availability and performance of the backend servers. If a backend server fails the health check, SLB stops routing requests to it and redirects the traffic to other healthy servers. This way, SLB can improve the system’s availability by eliminating single points of failure (SPOFs). Therefore, option A is a correct statement about SLB.

According to the same documentation1, SLB instances are assigned with public IP addresses or private IP addresses based on the network type. If you delete an SLB instance and create a new one, a new IP address will be allocated to the new instance. You cannot specify or reserve an IP address for an SLB instance. Therefore, option B is also a correct statement about SLB.

Option C is incorrect, because SLB does not require you to install or configure any SLB agent on the backend servers. You only need to add the backend servers to the SLB instance and configure the listener and the server group. SLB will automatically distribute the traffic to the backend servers based on the load balancing algorithm and the health check status2.

Option D is also incorrect, because SLB does not provide a function to automatically synchronize data among backend servers. SLB only handles the network traffic distribution and does not interfere with the data on the backend servers. You need to use other methods or tools to synchronize data among backend servers, such as rsync, lsyncd, or Alibaba Cloud Data Transmission Service (DTS)3.

References: Server Load Balancer:SLB overview, Add backend servers, and Data Transmission Service.

RDS for MySQL supports both full backups and incremental backups. A full backup is a complete backup of all data in a database. An incremental backup is a backup of only the data that has changed since the last backup. Incremental backups can reduce the backup time and storage space. You can configure the backup cycle and retention period for both types of backups in the RDS console or by using the API.

Alibaba Cloud CDN (Content Delivery Network) can be used with OSS to accelerate the delivery of static content by caching data at edge nodes closer to end-users. This combination is ideal for static websites, as CDN reduces latency and enhances the loading speed of web pages hosted on OSS. By serving content from multiple distributed nodes, CDN provides users with faster, more efficient access to static resources.

Cloud computing is characterized by large-scale infrastructure, high availability, on-demand service provisioning, and versatility in handling diverse applications and workloads. It supports both multi-tenant and single-tenant configurations, and although containerization is popular, cloud computing is not limited to container-based architectures.

ApsaraDB for RDS is a stable and reliable online database service that supports MySQL, SQL Server, PostgreSQL, MariaDB, and PPAS. ApsaraDB for RDS provides a read/write splitting feature that allows you to create read-only RDS instances, which can offload read requests from the primary RDS instance of your database system1. Read/write splitting is implemented by using a dedicated proxy endpoint, which routes read and write requests to different RDS instances based on the SQL statements and the read weights of the read-only instances2. By using ApsaraDB for RDS to implement read/write splitting, you can achieve the following benefits21:

Read requests are distributed to multiple instances. This can improve the read performance and availability of your database system, as well as balance the load among the read-only instances. You can specify the read weights of the read-only instances to control the distribution of read requests.

Read/write requests to the database are separated. This can reduce the pressure on the primary RDS instance and ensure the stability and security of the write operations. You only need to connect to the proxy endpoint, and the proxy will automatically route the read and write requests to the appropriate RDS instances.

The other statements are not correct, as write requests are not distributed to multiple instances, but only sent to the primary RDS instance2; and both read and write requests are not distributed to multiple instances, but separated by the proxy endpoint2. References: [ApsaraDB for RDS - Alibaba Cloud], Read/write splitting - - Alibaba Cloud Documentation Center, Use the read/write splitting feature to increase the processing capability of an ApsaraDB RDS instance

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 field1. 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

Alibaba Cloud VPC uses tunneling technology with unique tunnel IDs to create isolated virtual networks that offer similar isolation capabilities as VLANs in traditional networks. This allows each VPC to function as an independent, secure network environment within the cloud, ensuring traffic separation and resource isolation.

 A bastion host is a special-purpose computer on a network specifically designed and configured to withstand attacks. The computer generally hosts a single application, for example a proxy server, and all other services are removed or limited to reduce the threat to the computer. It is hardened in this manner primarily due to its location and purpose, which is either on the outside of a firewall or in a demilitarized zone (DMZ) and usually involves access from untrusted networks or computers. In the context of Alibaba Cloud, a bastion host can be used to securely access and manage multiple ECS instances in a VPC through the Internet. By applying an EIP and binding it to the bastion host, the administrator can use SSH or RDP protocols to log on to the bastion host from the Internet, and then use the same protocols to access other ECS instances in the VPC through the private network. This way, the administrator can avoid exposing all the ECS instances to the Internet, which would increase the risk of attacks and incur higher costs. The bastion host can also be configured with security policies and monitoring tools to enhance the protection of the ECS instances in the VPC. References: Bastion Host, Access an ECS Instance by Using a Bastion Host

Data Transmission Service (DTS) is a real-time data streaming service that supports data transmission between data sources such as relational databases, NoSQL, and Big Data (OLAP). DTS supports data migration, data synchronization, and change data subscription scenarios. DTS can migrate your data to and from most of the widely used commercial and open source databases. It supports homogeneous migrations such as MySQL to MySQL, as well as heterogeneous migrations between different database platforms, such as Oracle to MySQL. Migrations can be from on-premises databases to RDS or ECS, databases running on ECS to RDS, or vice versa, as well as from one RDS database to another RDS database. DTS also supports migrating data between RDS instances of different Alibaba Cloud accounts, as long as they are in the same region1. Therefore, the statement B. The data cannot be migrated is NOT correct for migrating self-built MySQL databases (running on ECS) to RDS. The other statements are correct, as the data can be imported via the Intranet, the public network, or by running mysqldump234. References:

1: Migrate Self-built Database to RDS - Alibaba Cloud

2: Migrating a Self-built MySQL Database to Alibaba Cloud RDS for MySQL with Minimal Downtime - Alibaba Cloud Community

3: Migrating Data from a Self-Managed SQL Server Database on an ECS to an ApsaraDB RDS for SQL Server Database

4: Migrate data between RDS instances of different Alibaba Cloud accounts,Data Transmission Service

CloudMonitor allows users to create custom monitoring metrics and report data, which can then be analyzed and used for alerts. Customized monitoring is flexible, with no set limits on the number of metrics, and users can report data from Alibaba Cloud servers or other devices.

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Latency on an RDS read-only instance can be caused by high loads on the instance itself, inadequate instance specifications, or excessive write operations on the master instance, as these factors directly impact replication delay and resource contention. However, a high load on the ECS instance connected to the RDS read-only instance would not inherently cause latency on the RDS instance, as the ECS and RDS operate independently in terms of processing.

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Data Transmission Service (DTS) is a real-time data streaming service that supports data transmission between data sources such as relational databases, NoSQL, and Big Data (OLAP). DTS supports data migration, data synchronization, and change data subscription scenarios. DTS can migrate your data to and from most of the widely used commercial and open source databases. It supports homogeneous migrations such as MySQL to MySQL, as well as heterogeneous migrations between different database platforms, such as Oracle to MySQL. Migrations can be from on-premises databases to RDS or ECS, databases running on ECS to RDS, or vice versa, as well as from one RDS database to another RDS database. DTS also supports database schema replication between instances, which means that DTS can automatically create the same schema as the source database in the target database. DTS also supports warning when source and destination has some unresolved conflict found, such as data type mismatch, primary key conflict, or foreign key constraint violation. DTS can help you resolve these conflicts by providing suggestions or allowing you to modify the data mapping rules. Therefore, the correct answer is C. Supports all of the above functions. References:

1: Data Transmission Service - Alibaba Cloud

2: What is Data Transmission Service? - Alibaba Cloud

3: Database Migration - AlibabaCloud

4: Cloud Migration without Stopping Services: Alibaba Cloud DTS

Certificates are mandatory when using the HTTPS protocol with Alibaba Cloud SLB to secure data transmission between clients and the SLB instance. HTTPS (HTTP Secure) requires an SSL/TLS certificate to encrypt the data, ensuring secure communication over the network. For protocols like HTTP or TCP, a certificate is not required, as they do not natively support encryption.

In Alibaba Cloud OSS, a bucket cannot be deleted until all contents, including files and incomplete multipart upload segments, are removed. This prevents accidental data loss by ensuring no objects remain in the bucket before deletion.

Alibaba Cloud Auto Scaling ensures transaction completeness during scaling activities. If the intended number of ECS instances cannot be added to the scaling group, Auto Scaling rolls back the entire activity, releasing any partially added instances. This behavior prevents incomplete scaling activities, ensuring the scaling action either fully succeeds or is reverted entirely.

Once a VPC is created in Alibaba Cloud, its CIDR Block cannot be modified. This design ensures stability and network consistency within the VPC. To change the network range, a new VPC would need to be created with the desired CIDR Block.

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A low CDN cache hit rate can be due to low website traffic, poor cache configurations (such as a short Cache Expiry Time), or the presence of dynamic resources that require frequent retrieval from the origin. Proper configuration of "Cache-Control" and "Expires" headers is necessary to ensure caching.

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The transmission acceleration service for OSS is a feature that allows you to access OSS buckets through a global acceleration endpoint, which can improve the upload and download speed of OSS data across regions. The global acceleration endpoint is a domain name that is resolved to the nearest OSS access point based on the network conditions of the client. This way, the data transmission distance is shortened and the network latency is reduced. Therefore, option C is the correct answer. References: Enable transfer acceleration, Map an acceleration endpoint

Alibaba Cloud OSS provides three primary access permissions for buckets: Private, Public-read, and Public-read-write.

Private: Only the owner has access to read or write data.

Public-read: The owner can read and write, but others can only read.

Public-read-write: The bucket is fully open for reading and writing by all users.There is no Private-read permission in OSS access control options, so option A is incorrect.

Before data communication is set up, the security groups match the security group rules one by one to query whether to allow access requests. If the protocol type, port range, authorization type, and authorization object of two security group rules are the same, the following rules apply:

If the two rules have the same priority, the rule of the denial policy takes effect first, and the rule of the allowed policy does not take effect. This is because the security group rules follow the principle of minimum permission, which means that the most restrictive rule is applied when there is a conflict.

If the two rules have different priorities, the rule with a smaller priority number takes effect. This is because the security group rules follow the principle of priority, which means that the rule with a higher priority (lower number) is applied when there is a conflict. References: ECS Security Groups - Alibaba Fundamentals - Cloud Academy, Security group rules - Elastic Compute Service - Alibaba Cloud Documentation Center

Alibaba Cloud provides two main products for Anti-DDoS protection: Anti-DDoS Origin Service, which protects against attacks at the origin server level, and Anti-DDoS Pro Service, which offers advanced DDoS mitigation for applications hosted on Alibaba Cloud. Security Center and Cloud Firewall offer different security functionalities but do not provide direct Anti-DDoS services.

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RDS accounts can be used to connect with the databases created on a given RDS instance. Each account can be bound with multiple databases. However, the read/write permissions of each database can be assigned to multiple RDS accounts, not just one. For example, you can create an account with read-only permission for all databases, and another account with read-write permission for a specific database. This way, you can manage the access control of your databases more flexibly and securely. References:  Introduction to ApsaraDB RDS - Alibaba Cloud Document Center - User Management - Account Permissions

CDN is most effective for scenarios with high repetitive access, where content is frequently requested and can be cached, such as static websites, video delivery, and application download sites. In contrast, a personal netdisk service typically involves unique, private files with low repeat access rates, making CDN less effective since the content is unlikely to be accessed by multiple users frequently, thus reducing the benefit of caching.

When using Auto Scaling with Server Load Balancer (SLB), both the scaling group and the SLB instance must reside in the same region. This is because region-specific configurations enable low-latency connections and proper integration between the resources, ensuring the scaling group can register with the SLB instance effectively.

Alibaba Cloud OSS ensures high reliability and availability by maintaining multiple copies of data across different physical locations, allowing it to recover within minutes in the event of hardware failures. This redundancy mechanism provides strong data durability and service continuity.

 The Alibaba Cloud CDN can directly accelerate access to the files stored in OSS and reduce OSS traffic costs. Alibaba Cloud CDN is a global network of points of presence (POPs) that are distributed across the globe. Alibaba Cloud CDN serves to reduce back-to-origin traffic. This in turn prevents network congestion and ensures that content is delivered with minimal latency across regions in various use cases1. Alibaba Cloud CDN caches resources from your origin servers on POPs located across the globe. Whenever customers access your resources, the resources are served from the nearest POP instead of the origin server. This helps prevent lengthy back-to-origin requests and reduces loads on origin servers, delivering better experience to your customers and reducing back-to-origin costs1. Alibaba Cloud CDN also provides IPv6 support on some POPs1. You can use Alibaba Cloud CDN to accelerate access to Object Storage Service (OSS). If you directly access OSS resources, the access speed varies based on the region in which the buckets are located and is limited by the outbound bandwidth of OSS2. The Internet traffic cost of CDN is lower than that of OSS, and the back-to-source traffic cost from CDN to OSS is also lower than a user access to OSS directly2. Therefore, using CDN can reduce the traffic cost of OSS. References: Use Alibaba Cloud CDN to accelerate access to OSS, What is Alibaba Cloud CDN?