Slow Start

If you enable slow start, the load balancer linearly increases the proportion of requests to the new backend servers added to the backend server group. When the slow start duration elapses, the load balancer sends full share of requests to backend servers and exits the slow start mode. For details about how to set weights for backend servers, see Backend Server Weights.

Slow start gives applications time to warm up and respond to requests with optimal performance.

Slow start is only available for HTTP and HTTPS backend server groups of dedicated load balancers.

Backend servers will exit slow start in either of the following cases:

The slow start duration elapses.
Backend servers become unhealthy during the slow start duration.

Constraints

Weighted round robin must be selected as the load balancing algorithm.
Slow start takes effect only for new backend servers and does not take effect when the first backend server is added to a backend server group.
After the slow start duration elapses, backend servers will not enter the slow start mode again.
Slow start takes effect when health check is enabled and the backend servers are running normally.
If health check is disabled, slow start takes effect immediately.

Enabling or Disabling Slow Start

Log in to the management console.
In the upper left corner of the page, click and select the desired region and project.
Click in the upper left corner to display Service List and choose Networking > Elastic Load Balance.
In the navigation pane on the left, choose Elastic Load Balance > Backend Server Groups.
On the Backend Server Groups page, locate the backend server group and click Edit in the Operation column.
Figure 1 Modifying a backend server group
In the Modify Backend Server Group dialog box, enable or disable Slow Start.
If you enable it, you need to set the slow start duration. The duration ranges from 30 to 1200. When the slow start duration elapses, the load balancer sends full share of requests to backend servers and exits slow start.
Click OK.