AS adjusts resources for an application system based on demand, thereby enhancing cost management. Resources are adjusted in the following ways:
AS adjusts resources when an alarm policy is triggered. For details, see section Dynamically Expanding Resources.
AS adjusts resources when a periodic or scheduled policy is triggered. For details, see section Expanding Resources as Planned.
Resources are adjusted if you manually change the expected number of instances, or add instances to or remove instances from an AS group. For details, see section Manually Expanding Resources.
For example, a common web application used for buying train tickets and running on the public cloud is rarely used during Q2 and Q3 and is frequently used in Q1 and Q4. Generally, a large number of servers are added to the system, as shown in Figure 1. Alternatively, the capacity required for processing the average demand is added, as shown in Figure 2. However, these two solutions may waste resources or cannot meet demand spikes. After you enable AS for your application, AS automatically adjusts the number of servers based on requirements to reduce cost and meet demand spikes.