tencent cloud

Feature Overview

CFS provides the scheduled snapshot feature that allows developers to flexibly configure snapshot policies.
The following table describes the scheduled snapshot policies recommended for different businesses.

Scenario	Snapshot Policy	Snapshot Retention Period
Core product/service	Use scheduled snapshots, with the policy set to once per day.	7 to 30 days
Non-core and non-data product/service	Use scheduled snapshots, with the policy set to once per week.	7 days
Archive	Scheduled snapshot is not required. You can create snapshots manually whenever needed.	One month to several months
Test	Scheduled snapshot is not required. You can create snapshots manually whenever needed.	Deleted after being used

Policy Description

The following table describes the content and features of scheduled snapshot policies, which help you better use snapshots in your businesses.

Item	Description
Object	All file systems
Policy	The point in time for scheduled snapshot creation can be accurate to every hour or every day. A scheduled snapshot policy is valid permanently after being set. If you modify a scheduled snapshot policy, it takes effect immediately.
Scheduled termination (Important)	Scheduled snapshots can be terminated periodically. After you set a snapshot lifecycle (1–30 days), scheduled snapshots are automatically deleted upon expiration, which reduces the backup costs. If you do not set a scheduled termination policy, scheduled snapshots will be stored permanently.
Batch	You can select multiple file systems and batch apply the same scheduled snapshot policy for them.
Naming rule	Scheduled snapshots are named in the format of `auto_policy_cfsidyyyyMMddHH`. `cfsid` is the file system ID, `yyyyMMdd` is the snapshot creation date, and `HH` is the hour. You can also manually modify snapshot names. For example, `auto_policy_cfs-2cj5yj0f2021090923` indicates a snapshot that was automatically created on 2021-09-09 23:00:00 for the file system cfs-2cj5yj0f.
Lifecycle (Important)	Snapshot lifecycles vary depending on the snapshot creation method: Manually created snapshots are permanently stored by default as long as the account balance is sufficient. Scheduled snapshots can be terminated periodically or permanently stored.
Snapshot conflict	Scheduled snapshots do not conflict with custom snapshots in use. However, they may conflict with each other on the creation time. When a snapshot is automatically created for a file system, you can create a custom snapshot only after automatic snapshot creation is complete, and vice versa. If there is a large amount of data in the file system and the time for automatically creating a snapshot exceeds the interval between two time points for automatic snapshot creation, a snapshot is not automatically created in the next time point. For example, if you set 9:00, 10:00, and 11:00 as the time points for scheduled snapshot creation and it takes 70 minutes to create the snapshot at 9:00 (that is, the creation of this snapshot will be completed at 10:10), the next snapshot will not be created at 10:00, but at 11:00.
Snapshot quota	Each file system has a certain snapshot quota. If the number of snapshots on a file system has reached the quota limit, the scheduled snapshot task will be suspended or blocked. The snapshot quota is used to prevent continuous increase in the storage costs if developers forget a scheduled snapshot policy.
ASP	Indicates the scheduled snapshot policy, that is, Auto Snapshot Policy.
ASP quota	A single Tencent Cloud account can set a maximum of 30 ASPs in each region. An ASP can be associated with a maximum of 200 file systems.
Retention period	The console displays the repossession countdown for scheduled snapshots. You can manually change the retention period of scheduled snapshots to permanent. Manually created snapshots are permanently stored.
ASP pause	An ASP can be manually paused. After it is paused, snapshots are no longer automatically created. However, lifecycles of previously created snapshots are not affected. They will be periodically terminated or permanently stored based on configured rules.
Operation log	Show the creation process of all scheduled snapshots, same as that of manually created snapshots.

Directions

Creating a scheduled snapshot policy

Note：

A single Tencent Cloud account can set a maximum of 30 scheduled snapshot policies in each region.

1. Log in to the CFS console and go to the Snapshot Policies page.
   

2. Select a region.

3. Click Create Policy.
   

4. In the Create Policy pop-up, set parameters as needed and click Confirm.

   Parameter	Configuration
   Name	Required. The name of a scheduled snapshot policy. It can contain up to 60 characters.
   Region	Required. This parameter cannot be changed on the current page. For more information on how to set this parameter, see Step 2.
   Backup Day	Required. The days to automatically create snapshots. Value range: Every Sun to Every Sat
   Backup Time	Required. The time to automatically create snapshots. Value range: 00:00 - 23:00. Due to server performance issues, the actual scheduled snapshot creation time may be slightly different from the time set here. In this case, data in a snapshot is based on the actual creation time.
   Snapshot Retention	Required. Retained for a fixed number of days. The value range is 1 to 30 days. The default value is 30 days. Permanent

Assigning a file system

Note：

A scheduled snapshot policy can be associated with a maximum of 200 file systems.

1. Log in to the CFS console and go to the Snapshot Policies page.

2. Select a region.

3. Click Assign File System in the row of the target policy.

4. In the Assign File System pop-up, select the file systems to assign.

5. Click Confirm.

Enabling or disabling a scheduled snapshot policy

1. Log in to the CFS console and go to the Snapshot Policies page.
2. Select a region.
3. Find the target policy and click the button in the Scheduled Snapshot column to enable or disable the scheduled snapshot policy.

Modifying a scheduled snapshot policy

1. Log in to the CFS console and go to the Snapshot Policies page.
2. Select a region.
3. Find the target policy and click Modify Policy in the Operation column.
4. In the Modify Policy pop-up, modify related parameters and click Confirm. For more information about parameter descriptions, see Step 4).

Deleting a scheduled snapshot policy

1. Log in to the CFS console and go to the Snapshot Policies page.
2. Select a region.
3. Delete a scheduled snapshot policy as follows:
   Click More > Delete Policy in the row of the target policy.

Setting permanent storage for scheduled snapshots

Note：

If Snapshot Retention is set to Permanent for a scheduled snapshot policy, you do not need to perform the following operations for snapshots automatically created using this policy.

1. Log in to the CFS console and go to the Snapshot List page.
2. Select a region.
3. Click the ID of the target snapshot.
4. On the details page, click Permanent to permanently store the snapshot, and Snapshot Retention of the snapshot is changed to Permanent.