Terms

This topic describes the terms used in Elastic Compute Service (ECS).

No.	Term	Description
1	ECS instance	An ECS instance is a virtual server that includes basic components such as vCPUs, memory, an operating system (OS), network configurations, and disks.
2	image	Images contain information that is necessary to run ECS instances, such as OSs and initialization data of applications.
3	disk	Disks are block-level EBS devices that use a triplicate mechanism to ensure high data durability for ECS instances.
4	snapshot	A snapshot is a point-in-time backup of a disk and is used to back up or restore the disk.
5	security group	A security group is a virtual firewall that is used to control the inbound and outbound traffic of ECS instances in the security group.
6	deployment set	Deployment is set to support the high availability strategy. After you apply a high availability strategy to a deployment set, all the instances within the deployment set are distributed across different physical servers to ensure business availability and disaster recovery capabilities at the underlying layer.