Server Load Balancer

Respond to sudden traffic spikes and minimize response time with Server Load Balancer

Alibaba Cloud Server Load Balancer (SLB) distributes traffic among multiple instances to improve the service capabilities of your applications. You can use SLB to prevent single point of failures (SPOFs) and improve the availability and the fault tolerance capability of your applications.


Same-city disaster recovery
Supports high availability across zones and failover within 30 seconds.
Traffic distribution
Supports automatic traffic distribution among multiple instances to improve the servicing capabilities of your applications.
Ease of use
Provides multiple billing standards, billing methods, and service management approaches.
Extremely high performance
Provides guaranteed-performance instances and supersize instances.


  • Compatibility with multiple protocols

    Supports multiple protocols to meet your business needs.

    Layer-4 and Layer-7 load balancing

    Supports Layer-4 load balancing over TCP or UDP and Layer-7 load balancing over HTTP or HTTPS.

    Certificate management

    Provides a centralized HTTPS certificate management system to ensure reliable and secure data transmission.

  • Multi-layer disaster recovery

    Supports multi-layer disaster recovery and high availability.

    Health check

    Supports periodical instance status check. When SLB detects a faulty instance, it stops distributing traffic to the instance to ensure the availability of your service.

    Multiple zones

    Supports multi-zone deployment in specific regions to implement same-city disaster recovery.

    Cluster deployment and session synchronization

    Supports cluster deployment and instance session synchronization to upgrade and perform maintenance on instances and clusters with zero service downtime.

  • Extremely high performance

    The first cloud computing vendor that provides guaranteed-performance instances.

    Guaranteed-performance instances

    Provides multiple types of guaranteed-performance instances with dedicated resources.

    Supersize instances

    Provides supersize instances to offer better performance.

  • Efficient scheduling

    Supports multiple scheduling algorithms and distribution modes to improve the efficiency of application deployment.

    Scheduling algorithms

    Supports the weighted round-robin and least-connections scheduling algorithms. These algorithms allow you to distribute traffic based on your business needs.

    Traffic distribution based on domain names and URLs

    Distributes traffic based on domain names and URLs to improve the efficiency of your applications.

  • Session persistence

    Redirects a client’s requests that have been received within a specified period of time to the same instance to maintain the session.

    Source IP-based session persistence

    Supports load balancing over TCP to maintain sessions.

    Cookie-based session persistence

    Supports load balancing over HTTP or HTTPS to maintain sessions.

  • Multiple SLB management approaches and billing methods

    Supports multiple instance types and billing methods to meet your business needs, and provides multiple methods for you to manage SLB.

Common Scenarios

  • Handling mass video and audio streams
  • Static and dynamic content separation for online games
  • Multi-layer disaster recovery architecture
  • Distribution of mass traffic
Handling mass video and audio streams

Mass data distribution

Supports the automatic distribution of mass video and audio.

Users using video and audio playback clients need to frequently interact with casters in real time. Mass requests from users may cause a broadcasting service instability. This poses a great challenge to the flexibility, stability, and availability of the entire broadcasting system.


  • Improvement of horizontal scaling capability

    Allows you to dynamically add or remove instances based on the amount of traffic.

  • Distribution of mass traffic

    Distributes mass traffic among multiple instances to meet your business needs.

  • Improvement of application high availability

    Supports health check to block malfunctioned instances in real time and improve the stability of your applications.


Static and dynamic content separation for online games

Static and dynamic content separation

Static and dynamic request separation for fast and stable content delivery

Game services always need to load a large amount of static resources, such as pictures. You can use CDN to accelerate access to static resources for players globally. Burst traffic occurs when players interact with each other in a game. You must use SLB to distribute the traffic to ensure latency-free in-game interaction.


  • Distribution of dynamic requests

    Distributes dynamic requests among multiple instances in real time.

  • Acceleration of static content delivery

    Works with Object Storage Service (OSS) to cache static content and incorporates CDN to optimize route selection and accelerate static content delivery.

Integrations and Configurations

Multi-layer disaster recovery architecture

Multi-layer disaster recovery architecture

Disaster recovery across regions and zones

Alibaba Cloud DNS allows you to direct requests to relevant business systems across regions through intelligent address resolution. SLB enables you to distribute mass traffic and build a multi-layer disaster recovery architecture across regions and zones.



    The GEO DNS service can return the optimal IP address to users. This allows the users to quickly and smoothly access the website.

  • Traffic distribution

    Distributes mass traffic among multiple instances to meet the requirements of business development.

  • Multi-layer disaster recovery

    Supports cross-region high availability based on Alibaba Cloud DNS and cross-zone high availability based on SLB.

Integrations and Configurations

Distribution of mass traffic

Distribution of mass traffic

Distribution of mass user requests

SLB deploys instances across regions and uses these instances to load share mass user requests received on your video website to ensure the stability of your business. However, you must ensure high-speed interconnections between these instances.


  • High performance

    Express Connect provides a bandwidth of 10 GB for intercommunication between VPCs. This allows you to use a large amount of applications.

  • Traffic distribution

    Distributes traffic among multiple instances to improve the capability of horizontal scaling.


Certification course: Handle Large Traffic with Load Balancer

In this online course, we teach the basics of load balancing, principles and scenarios, and master cloud platform load balancing features and usage.

0.01 USD

Original Price: USD 10.00

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