Hybrid Backup Recovery (HBR) provides the application-consistent backup feature based on Cloud Assistant and the
backup service. The application-consistent backup feature helps prevent unexpected
startup operations during data restore, for example, log restore operations at the
startup of database applications. This way, all applications start in a consistent
state.
Prerequisites
- Your ECS instance runs one of the following operating systems:
- Windows: Windows Server 2019, Windows Server 2016, and Windows Server 2012.
- Linux: CentOS version 7.6 and later, Ubuntu version 18.04 and later, and Alibaba Cloud
Linux version 2 (2.1903 LTS 64-bit).
- All disks that are attached to your ECS instance are enhanced SSDs (ESSDs) and the
file systems are ext3, ext4, XFS, or New Technology File System (NTFS).
- Your ECS instance is created in the Singapore (Singapore) or China (Hong Kong) region.
Background information
By default, Hybrid Backup Recovery (HBR) creates crash-consistent backup files based on the Alibaba Cloud snapshot service.
If you enable the application-consistent backup feature when you create a backup file
for an ECS instance, HBR creates an application-consistent backup file based on the
actual scenario.
The application-consistent backup feature helps back up in-memory data and in-progress
database transactions when backup files are being created. This way, the consistency
between the application data and database transactions is ensured. The application-consistent
backup feature helps prevent data corruption, data loss, and log restore operations
at the startup of database applications. This way, all applications start in a consistent
state.
Step 1: Configure a RAM role for the ECS instance
Before you enable the application-consistent backup feature, you must configure a
RAM role for the ECS instance.
- Log on to the RAM console by using your Alibaba Cloud account.
- Create a RAM role for the application-consistent backup feature. For more information,
see Create a RAM role for a trusted Alibaba Cloud service.
The following figure shows how to create the AppSnapshotRoleName RAM role.

- Create a policy for the application-consistent backup feature. For more information,
see Create a custom policy.

Create the AppSnapshotPolicy policy, which grants the permissions to query snapshot
details, create snapshots, configure tags, and query disk details. You can use the
following policy:
{
"Version": "1",
"Statement": [
{
"Effect": "Allow",
"Action": [
"ecs:DescribeSnapshot*",
"ecs:CreateSnapshot*",
"ecs:TagResources",
"ecs:DescribeDisks"
],
"Resource": [
"*"
],
"Condition": {}
}
]
}
- Attach the AppSnapshotPolicy policy to the AppSnapshotRoleName RAM role. For more
information, see Grant permissions to a RAM role.
- Attach the AppSnapshotRoleName RAM role to the ECS instance. For more information,
see Attach an instance RAM role to an ECS instance.
Step 2: Enable the application-consistent backup feature
For Windows ECS instances, you can use Volume Shadow Copy Service (VSS) to implement
application consistency.
For Linux ECS instances, you must configure shell scripts (pre-freeze and post-thaw
scripts) based on the applications deployed on the instances to implement application
consistency.
- Log on to the HBR console.
- In the left-side navigation pane, choose .
- In the top navigation bar, select a region.
- In the upper-right corner of the page, click Add ECS Backup.
- In the Create ECS Protection Plan dialog box, configure the following settings:
- Specify the backup objects and click Next.
Important
- You must select the ECS instances and disks that you want to back up. Protect All
Disks is turned on by default. If you want to protect all disks of an ECS instance,
turn on Protect All Disks. In this case, the disks that are later attached to the ECS instance are also protected.
If you want to protect only specific disks, turn off Protect All Disks.
- You can associate up to 99 ECS instances with a backup policy.
- Hybrid Backup Recovery (HBR) automatically checks whether the selected ECS instances support snapshot-consistent
groups. HBR automatically creates a snapshot-consistent group for the ECS instances
that support snapshot-consistent groups. If an ECS instance does not support snapshot-consistent
groups, HBR ensures only the crash consistency of disks. For more information, see
Create a snapshot-consistent group.
- Configure the backup settings and click OK.
- Configure the backup mode.
You can select Manual Backup or Auto Backup. The following list describes the parameters.
- Manual Backup
- Only one backup file is created for the selected ECS instances at the current point
in time.
- You must specify the retention period of the backup data, whether to enable application-consistent
backup, and whether to enable cross-region replication.
- Auto Backup
- If you select a single ECS instance, you can turn on Application Consistent Backup to enable the application-consistent backup feature.
For more information, see Enable the application-consistent backup feature.
- Optional:Turn on Replication to Other Region to enable the cross-region replication feature, and then configure the parameters.
The following table describes the parameters.
Parameter |
Description |
Destination Region |
If you enable the cross-region replication feature, the backup files that are created
by the backup plan are automatically replicated to the specified destination region.
If an ECS instance is infected with viruses or data is lost due to accidental deletion,
you can use the backup files replicated to the destination region to create another
instance to restore data.
|
Retention Period |
The retention period of the backup data in the destination region. Unit: days, weeks,
months, or years.
|
- Select Application Consistent Backup.
- Enable the application-consistent backup feature for a Windows ECS instance
Note If you select
Application Consistent Backup, you must install a Cloud Assistant client on the ECS instance. In Windows, the process
of a Cloud Assistant client is named
AliyunService
. For more information, see
Overview.
- Enable the application-consistent backup feature for a Linux ECS instance
Write the application pre-freeze and post-thaw scripts based on the applications deployed
on the ECS instance and upload the scripts to the ECS instance.
You can use the FTP service or Cloud Assistant to upload the application pre-freeze
and post-thaw scripts to the ECS instance.
- Application pre-freeze scripts: Run the
chmod 700 /tmp/prescript.sh
command to grant the read, write, and execute permissions on the scripts only to
the root user. /tmp/prescript.sh is the save path of the scripts.
- Application post-thaw scripts: Run the
chmod 700 /tmp/postscript.sh
command to grant the read, write, and execute permissions on the scripts only to
the root user. /tmp/postscript.sh is the save path of the scripts.
Important
- If Application Consistent Backup is selected and the scripts are configured as expected, HBR creates application-consistent
backup files.
- If Application Consistent Backup is selected but no scripts are configured or the scripts are not configured as expected,
HBR creates file system-consistent backup files.
Sample scripts for the application-consistent feature:
Note If you select
Application Consistent Backup, you must install a Cloud Assistant client on the ECS instance. In Linux, the process
of a Cloud Assistant client is named
aliyun.service
. You can run the
ps aux|grep aliyun.service
command to check whether a Cloud Assistant client is installed. For more information,
see
Overview.
- Click OK.