The next section we will cover is ECS Snapshots. Snapshots are complete, read-only copies of disk data at certain points in time. You can use snapshots for the following scenarios: 

Disaster recovery and backup: You can create a snapshot for a disk, and then use the snapshot to create another disk to implement zone- or geo-disaster recovery.

Environment clone: You can use a system disk snapshot to create a custom image, and then use the custom image to create an ECS instance to clone the environment.

Data development: Snapshots can provide near-real-time production data for applications such as data mining, report queries, and development and tests.

Enhanced fault tolerance: You can roll a disk back to a previous point in time by using a snapshot to reduce the risk of data loss caused by an unexpected occurrence. You can create snapshots on a regular basis to prevent losses caused by unexpected occurrences. These unexpected occurrences can include, for example, writing incorrect data to disks, accidentally deleting data from a disk, accidentally releasing ECS instances, data errors caused by application errors, and data loss due to hacking attempts.

Also, you could create a snapshot before you perform high-risk operations, such as changing operating systems, upgrading applications, and migrating business data.

In any of these scenarios, data can be retrieved from a snapshot.

Snapshots can be created manually or automatically by creating a snapshot policy. Up to 64 snapshots can be created per disk and each snapshot is an incremental copy of the previous snapshot. When the maximum number of snapshots has been reached the oldest snapshot is deleted as a new one is created.

Snapshots are not free, however, and are charged based on the storage space used and the amount of time they are kept.

Lectures

Overview - ECS Concepts - ECS Instances - ECS Images - ECS Storage - ECS Security Groups - ECS Networking - ECS Demo