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Which of the following statements is NOT correct, when comparing RDS with a self-built database?
A. Self-built database support quick deployment and elastic scaling.
B. RDS requires no O&M while self-built database require a dedicated DBA for maintenance, which results in high HR costs.
C. RDS features a high availability of 99 95% while self-built databases require you to implement data protection primary-standby replication, and RAID all by yourself.
D. RDS provides automatic backup while self-built databases require you to prepare storage space for backup copies and regularly verify that these copies can be restored.
Explanation: The statement A is not correct, because self-built databases do not support quick deployment and elastic scaling. On the contrary, self-built databases require hardware procurement, data center hosting, and machine deployment, which can be time consuming and costly. Moreover, self-built databases have low resource utilization, as they have to accommodate peak traffic requirements, while RDS can scale elastically according to the actual demand. References: = ApsaraDB for RDS vs. Self-built Databases - Alibaba Cloud
RDS provides whitelist access policies. You can set permitted IP addresses and IP network segments to effectively prevent hackers from attacking the server by port scanning.
A. True
B. False
Explanation: RDS provides whitelist access policies. You can set permitted IP addresses and IP network segments to effectively prevent hackers from attacking the server by port scanning1. A whitelist is a list of IP addresses or CIDR blocks that are allowed to access an RDS instance. By default, the whitelist is empty, which means that no IP address can access the RDS instance. You can add IP addresses or CIDR blocks to the whitelist to allow access from specific sources. You can also modify or delete the whitelist as needed2. Whitelist access policies help improve the security of your RDS instance and protect your data from unauthorized access3.
Auto Scaling is a management service that can automatically adjust elastic computing resources based on your business needs and policies It supports adding an existing ECS instance into the scaling group but imposes certain requirements on instance region In this case, which of the following statements is true?
A. The instance and the scaling group must be in the same region and zone.
B. The instance and the scaling group must be in the same region but not necessarily the same zone.
C. Each scaling group can span up to two regions. After adding the ECS instance, the number of regions of all the ECS instances in the scaling group must be no greater than two.
D. The instance and the scaling group can be in different regions and zones.
Explanation: According to the Alibaba Cloud documentation1, Auto Scaling is a service that automatically adjusts the number of elastic computing resources based on your business demands and policies. When the demand for computing resources increases, Auto Scaling automatically adds ECS instances to ensure sufficient computing capabilities. When the demand decreases, Auto Scaling automatically removes ECS instances to reduce costs. Auto Scaling supports adding an existing ECS instance into the scaling group, but the instance must meet some requirements1. One of the requirements is that the instance and the scaling group must be in the same region. However, they do not have to be in the same zone. A zone is a physical area within a region that has independent power grids and networks. A region is a geographic area where Alibaba Cloud deploys its resources. Therefore, the correct answer is B.
A video company uses SLB to distribute user requests to 20 ECS instances with the same configuration to response these requests. As the Spring Festival approaches, service traffic would double during holidays (based on past experience). Thus, you use Auto Scaling to elastically adjust computing resources. Since the services is online for many years, you have historic records that can help predict the upcoming service traffic and choose the scaling mode freely. In this scenario, which of the following options are feasible and with minimum operation efforts? (Number of correct answers: 2)
A. Cloud monitor and event-triggered task: Dynamically adds ECS instances during resource shortage and reduces ECS instances during idle hours by monitoring the CPU utilization rate and workload
B. Scheduled task: Increases the number of ECS instances to 40 on the first day of the holidays and reduce the number to 20 after the holidays
C. Manual mode: Set the minimum number of instances to 40 on the first day of the holidays and change the number to 20 after the holidays.
D. Healthy check mode: Ensures that all the current ECS instances in scaling groups are working correctly to meet user access requests.
Explanation: According to the Alibaba Cloud Academy, Auto Scaling supports three scaling modes: manual mode, scheduled task, and cloud monitor and event-triggered task. Manual mode requires manual intervention to adjust the number of ECS instances, which is not feasible and with minimum operation efforts. Scheduled task allows you to set the time and number of ECS instances to be added or removed in advance, which is suitable for predictable traffic changes. Cloud monitor and event-triggered task allows you to set the monitoring metrics and thresholds for scaling actions, which is suitable for dynamic traffic changes. Healthy check mode is not a scaling mode, but a feature of SLB to ensure the availability of ECS instances behind the load balancer. References: : ACP Cloud Computing Certification Preparation Course - Auto Scaling, : ACP Cloud Computing Certification Preparation Course - Server Load Balancer
Many of Alibaba Cloud services provide highly reliable data storage capacity. For example, Object Storage Service (OSS) promises that its data reliability is no less than 99 99999999%. This high data reliability is solely achieved by RAID 0+1 redundancy technology.
A. True
B. False
Explanation: Alibaba Cloud Object Storage Service (OSS) does not solely rely on RAID 0+1 redundancy technology to achieve high data reliability. OSS uses a distributed system architecture to store data across multiple devices and servers. OSS also supports crossregion replication (CRR) to replicate data across different regions for disaster recovery. OSS is designed for 99.9999999999% (12 9’s) data durability and 99.995% service availability12. References: Object Storage Service (OSS) - Alibaba Cloud What is OSS? - Object Storage Service - Alibaba Cloud Documentation Center
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