Alibaba Cloud ECS cloud server snapshot operation

1. The concept of snapshot

1.1 What is a snapshot

A snapshot is a data backup of the state of the cloud disk at a certain point in time. When the server fails one day, we can quickly restore the system through the snapshot.

Alibaba Cloud snapshot service is equivalent to a data backup method, which can create snapshots for all types of ECS cloud disks, used to backup or restore cloud disk data, and is an efficient data disaster recovery method.

We can create a snapshot of the cloud disk of a certain ECS instance, and then make the snapshot into a system image, and create an ECS cloud server through the image.

Alibaba Cloud snapshots are divided into manual snapshots and automatic snapshots. Snapshots can be set when purchasing ECS.

Snapshot function: create a snapshot based on the cloud disk, quickly recover when the cloud disk fails, and make the snapshot into a system image in the same region or a different region, so as to create the same ECS cloud server, or create a new cloud through the snapshot Disk, so as to analyze the problem, you can also copy the snapshot to other regions for use.

1.2. Cloud disk incremental snapshot

The first snapshot of Alibaba Cloud's cloud disk snapshot is a full snapshot and does not back up empty data blocks. For example, our cloud disk has 200G storage control, but we only use 100G, so the first snapshot will only back up the used 100G storage space The data, the unused empty data blocks will not be backed up, and each subsequent snapshot backup is an incremental snapshot, backing up the data that has changed since the last snapshot.

When creating each snapshot, the file system checks the data in the cloud disk in blocks, and only the changed data blocks will be backed up in the snapshot.

2. Manually create a snapshot for the cloud disk

2.1. Create a snapshot

1) Find storage and snapshots on the ECS instance management page ---> cloud disk ---> select the cloud disk to be snapshotted (according to actual needs, make snapshot backups for the system disk and data disk respectively) ---> create a snapshot .

We create a snapshot of the system disk.

2) Set the name of the snapshot. The name should be meaningful and convenient for query.

Let's set it to Web-01-Kodcloud-first snapshot and click create.

3) Snapshot Here you can see the snapshot information we created.

You can see the creation time, progress, and status of the snapshot. In the operation column, you can roll back the snapshot, create a mirror image, copy the snapshot (you can copy the snapshot to other regions), and other functions.

2.3. Simulate ECS server failure

Directly delete the / directory of the ECS server.

At this time, the services provided by the ECS cloud server are unavailable.

2.3. Restoring ECS based on snapshot rollback disk

We have just created a snapshot, and the rollback operation will be performed below.

1) First shut down the ECS instance, the stop time may be longer.

2) Find the snapshot corresponding to ECS ---> rollback disk.

3) Confirm rollback.

4) After the rollback is successful, the ECS server will automatically start

2.4. Log in to ECS to check whether the system is normal

The system returns to normal.

3. Automatically create snapshots for cloud disk settings

3.1. Create an automatic snapshot policy

1) Click Snapshot--->Automatic Snapshot Policy--->Create Policy.

2) Set the name of the policy, set the time point for creating snapshots, set the period for creating snapshots, and set the retention time of snapshots.

3) The policy was created successfully

3.2. Set automatic snapshot policy for cloud disk

1) Click to set automatic snapshot policy

2) Turn on the automatic snapshot policy ---> the snapshot automatic backup policy associated with the creation.

3.3. ECS sets an automatic snapshot policy for the cloud disk at the time of purchase

In the snapshot service in the basic configuration, select our automatic snapshot policy, and create a snapshot policy first.

3.4. Automatic snapshot has taken effect