Alibaba Cloud SLB can distribute user requests to backend ECS instances, but these ECS instances do not have to have the same specification (CPU, Memory). SLB virtualizes the added group of ECS instances in the same region into an application pool, and you can manage backend servers through either the default server group, a primary server group, or VServer groups. You can add ECS instances of different specifications to the same server group or VServer group according to your needs. SLB supports weighted round-robin (WRR) and weighted least connections (WLC) algorithms to balance the load among backend servers with different weights.  References :

SLB overview - Alibaba Cloud

Backend server overview - Alibaba Cloud

What is Server Load Balancer and How It Works - Alibaba Cloud

Server Load Balancer - Alibaba Cloud

Alibaba Server Load Balancer (SLB) Course - Cloud Academy

To isolate ECS instances within different VSwitches in a VPC while allowing them to access the internet and other intranet resources, each VSwitch ' s instances should be in separate Security Groups. By configuring each group to allow all VPC CIDR blocks first and then restricting access to other VSwitch CIDR blocks with a higher priority rule, instances in each VSwitch are isolated without affecting the VPC ' s external connections. This approach follows Alibaba Cloud ' s Security Group best practices and CIDR-based access control within VPC environments.

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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 cross-region 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 availability 1 2 .  References :

Object Storage Service (OSS) - Alibaba Cloud

What is OSS? - Object Storage Service - Alibaba Cloud Documentation Center

Alibaba Cloud ApsaraDB for RDS offers read/write splitting capabilities, allowing you to distribute read requests to read-only instances and write requests to the primary instance. This setup improves database performance under high traffic by optimizing read workloads, which is particularly useful for MySQL databases deployed in high-demand environments.

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 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 Center 1

Welcome to Alibaba Cloud and find out more detail about cdn real ip 2

Alibaba Cloud Security Center is designed to enhance the security of ECS instances by providing proactive monitoring, vulnerability detection, and protection against threats such as brute-force attacks. Security Center includes features such as brute-force attack detection, which will alert you to and help mitigate potential threats to your ECS instance.

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Alibaba Cloud SLB instances are assigned a public or private IP address when created, and this IP remains unchanged for the life of the SLB instance. The IP address will only be released when the SLB instance itself is deleted.