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    Cloud Backup:How do I resolve backup failures?

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    Cloud Backup:How do I resolve backup failures?

    Last Updated:Feb 04, 2026

    Troubleshoot backup failures systematically using a layered diagnostic approach. This guide provides unified troubleshooting workflows for all data sources, covering both client-based and service-based backup scenarios.

    Unified diagnostic framework

    Use this systematic approach to troubleshoot backup failures regardless of data source type:

    1. Perform basic checks: verify client status, network connectivity, and permissions

    2. Validate data source availability and configuration correctness

    3. Check service layer issues: API calls, backend task status, and system health

    4. Conduct advanced diagnostics: log analysis, performance bottlenecks, and edge cases

    This framework applies to all data sources mentioned in the following sections.

    Note

    This framework provides general troubleshooting methodology. Establish diagnostic thinking according to the four layers above, then apply the specific steps below to resolve backup failures for corresponding data source types.

    Step 1: Check whether a Cloud Backup client is installed

    • Data sources that do not require client installation

      When you back up Alibaba Cloud storage resources, such as OSS objects, NAS file systems, Tablestore instances, and ECS instances, in the Cloud Backup console for the first time, Cloud Backup uses the related service-linked roles to read these resources without installing a client. For more information about how to resolve backup failures and timeout errors in this scenario, see Step 2: Resolve backup failures when no Cloud Backup client is installed.

    • Data sources requiring client installation

      When you back up files, on-premises server files, ECS instances, on-premises databases (MySQL, Oracle, and SQL Server), VMs, and large-scale NAS file systems that are stored in self-managed data centers, you must install a Cloud Backup client. Cloud Backup clients support Windows and Linux operating systems. For more information about how to resolve backup failures and timeout errors in this scenario, see Step 3: Resolve backup failures when a Cloud Backup client is installed.

    For more information, see What is Cloud Backup? and Features supported by Cloud Backup.

    Step 2: Resolve backup failures when no Cloud Backup client is installed

    1. In the Cloud Backup console, modify and confirm the configurations as prompted.

    2. Troubleshoot a job that fails to back up OSS objects.

      • Status of the Backup Jobs: Failed (The OSS bucket does not exist.)

        The OSS bucket is deleted.

        • If the OSS bucket is deleted as expected, ignore the backup job status. To prevent additional backup storage fees, apply the following procedure: Click Storage Vaults in the navigation pane on the left, then locate and delete the storage vault.

        • If the OSS bucket is deleted unexpectedly, perform the following operation to restore the OSS bucket: Create an OSS bucket in the corresponding region and use the OSS bucket as the restoration destination to restore OSS objects. For more information, see Restore OSS objects.image.png

    3. Troubleshoot a job that fails to back up a NAS file system.

      If Status of the backup job is abnormal, take note of the following suggestions:

      • Status of the Backup Jobs: Failed (The path cannot be accessed.)

        The path specified by Source Paths in the backup plan does not exist. Change the source path in the backup plan and make sure that the network path exists. On the Backup Plans tab, find the file system and choose <hd> More </hd> > Modify Plan in the Actions column.image.png

      • Status of the Backup Jobs: Failed (The specified file system does not exist.)

        The NAS file system is deleted.

        • If the NAS file system is deleted as expected, ignore the backup job status. To prevent additional backup storage fees, apply the following procedure: Click Storage Vaults in the navigation pane on the left, then locate and delete the storage vault.

        • If the NAS file system is deleted unexpectedly, perform the following operation to restore the NAS file system: Create a NAS file system in the corresponding region and use the NAS file system as the restoration destination to restore NAS files. For more information, see Create a restore job for a single NAS file system in the same region.image.png

      • Status of the Backup Jobs: Failed (The mounting fails.)

        1. Click the Backup Plans tab and access the NAS file system on the Alibaba Cloud NAS tab. Make sure that VPC Default Permission Group (All Allowed) is used by the mount target created by Cloud Backup for the NAS file system, and that the default permission group allows access from all IP addresses (0.0.0.0/0). Otherwise, Cloud Backup cannot access the NAS file system. If the default permission group does not allow access from all IP addresses, contact Alibaba Cloud NAS technical support.

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        2. Alibaba Cloud NAS does not support the NAS Server Message Block (SMB) access control list (ACL) feature. If the ACL feature is enabled for your SMB file system, Cloud Backup cannot access the file system.

    4. Troubleshoot a job that fails to back up a Tablestore instance.

      If Status of the backup job is abnormal, take note of the following suggestions:

      • Status of the Backup Jobs: Failed

        Modify and confirm the configurations as prompted.

      • Instance Status of the Tablestore instance: Released

        The Tablestore instance has been deleted.

        • If the Tablestore instance is deleted as expected, ignore the backup job status. To prevent additional backup storage fees, apply the following procedure: Click Storage Vaults in the navigation pane on the left, then locate and delete the storage vault.

        • If the Tablestore instance is deleted unexpectedly, perform the following operation to restore the Tablestore instance: Create a Tablestore instance in the corresponding region and use the Tablestore instance as the restoration destination to restore the Tablestore instance. For more information, see Restore Tablestore tables.image.png

    Step 3: Troubleshooting Client-based Data Source Backup Failures

    1. In the Cloud Backup console, modify and confirm the configurations as prompted.

    2. Check the client status. For more information, see How do I check the status of a Cloud Backup client? and How do I troubleshoot and handle the status exceptions on a Cloud Backup client?

    3. If the backup job only fails occasionally, the failure is generally caused by network jitter or a temporary network disconnection. In this case, you do not need to perform any operations. After the network is recovered, the backup job is automatically executed. If the backup job fails continuously, we recommend that you use the diagnostic tool for Cloud Backup clients to monitor the network environment of the client. For more information about common network issues, see Common network issues.

    4. The local NAS mount failed.

      The configuration of the Cloud Backup client is incorrect, or the required tool is not installed.

      Windows client

      Files in an on-premises NAS file system are shared over a network. To back up or archive files in an on-premises NAS file system, select This user. The user must meet the following requirements:

      • The user has the permissions of the local administrator.

      • The user has the permissions to log on as a service.

        Perform the following steps:

        1. Open the Control Panel. In the window that appears, click Administrative Tools.

        2. Open Local Security Policy and choose Local Policies > User Rights Assignment.

        3. Turn on Log on as a service. In the dialog box that appears, add a user.

      • The user has the permissions to access files that are shared over a network.

      For more information, see How do I select a component and account when I install a Cloud Backup client?

      Linux client

      The Network File System (NFS) and SMB protocols are supported. You can select a tool based on the protocol of your NAS file system.

      • NFS tool

        • CentOS 

          sudo yum install nfs-utils

        • Ubuntu 

          sudo apt-get install nfs-common

      • SMB tool

        • Centos 

          sudo yum install cifs-utils

        • Ubuntu 

          sudo apt-get install cifs-utils

        • openSUSE 

          sudo zypper install cifs-utils

    5. If an out of memory (OOM) issue occurs due to insufficient resources, we recommend that you perform the following steps:

      1. Scale up resources.

      2. Split the source directory into multiple subdirectories. For more information, see Method 1: Split the source path.split directory

      3. Enable bandwidth throttling and configure related parameters in the backup plan.image.png

      4. Modify the configuration file of the Cloud Backup client to reduce the resource usage of the client. For more information, see Method 3: Reduce the resource consumption of the Cloud Backup client.

    6. If a timeout occurs, check the hbrclient.log file. If the keyword "Program Stopping!" appears, the client has been restarted. The following part lists the path of the hbrclient.log file:

      • On Linux: /opt/alibabacloud/hbrclient/logs/hbrclient.log

      • On Windows: C:\Program Files\Aliyun Hybrid Backup Service Client\logs\hbrclient.log

    References