This topic describes the limits that you must take note of when you use Hybrid Backup Recovery (HBR).

Database backup

  • On-premises database servers must be connected to virtual private clouds (VPCs) by using virtual private networks (VPNs) or Express Connect circuits. You must also make sure that you can use an HBR client to access one of the following CIDR blocks from an on-premises server: 100.64.0.0/10, 100.64.0.0/11, and 100.96.0.0/11.
  • HBR supports a limited number of database versions, operating systems, and backup features. For more information, see Database backup.

File backup

  • Backup clients for Windows support Volume Shadow Copy Service (VSS). You can create only one VSS snapshot at a time. If you use VSS, you cannot back up files from multiple paths or Universal Naming Convention (UNC) paths. You cannot use wildcards (*) or exclude files.
  • If HBR attempts to back up a file on which HBR has read permissions but the file is being modified by other applications, an incomplete backup occurs. You must ensure the integrity of backup data at the application layer.
  • If HBR attempts to back up a file on which HBR does not have read permissions or the file is locked by other processes, an incomplete backup occurs. The status of the backup job is displayed as partially completed when the job ends.

VMware VM backup

  • You must install a vSphere Web Client whose version is 5.5, 6.0, 6.5, 6.7, or 7.0 on each virtual machine (VM) for which you want to create a backup file.
  • A vCenter Server and an ESXi hypervisor must allow access from a backup gateway by using a fully qualified domain name (FQDN) or an IP address.
  • If you want to back up a VM, make sure that no snapshots are created for the VM. Otherwise, the following message appears when you select the VM: You cannot back up the virtual machine because you have already created a snapshot. If a snapshot exists, you must delete it before you can back up the VM.
  • You cannot back up VMs that have SCSI devices because vSphere VMs do not support shared SCSI devices.
  • The name of a VM that you want to back up cannot contain the following characters:

    ` ^ ~ = ; ! / ( ) [ ] { } @ $ \ & # % +

  • If you use Changed Block Tracking (CBT) to perform an incremental backup for a VM, the backup attempt fails in the following scenarios:
    • The hardware version of the VM is earlier than version 7.
    • CBT is disabled on the VM.
    • The disk of the VM uses raw device mapping (RDM) in physical compatibility mode.
    • The disk mode of the VM is independent_persistent or independent_nonpersistent.
  • The hardware version of the VM must be version 10 (corresponding to ESXi 5.5) or later.

SAP HANA backup

You can install only one SAP HANA instance on an ECS instance. Otherwise, the following error message appears: Failed to install SAP HANA.

NAS backup

NAS backup does not support access control lists (ACLs) for Server Message Block (SMB) file systems. For more information, see Use the ACL feature of a NAS SMB file system.

OSS backup

  • HBR cannot back up or restore symbolic links, object ACLs, or objects in archive buckets.
  • To improve the performance of incremental backup, HBR uses the latest OSS inventory list within the last seven days to back up data.
    The system may require a short period of time to generate an OSS inventory list. When you use the OSS inventory list, take note of the following limits:
    • If no inventory list is detected by a running backup job, the backup job fails.
    • If a backup job detects that the OSS inventory list remains the same as the OSS inventory list for the previous backup, the backup job fails.
    • If a backup job is triggered, HBR uses only the latest OSS inventory list to back up data. After a backup job is completed, the objects that you add to the OSS inventory list are backed up in the next backup cycle.
    • The interval at which backup jobs are performed must be greater than or equal to the interval at which OSS inventory lists are generated. This way, you can use an OSS inventory list each time you run a backup job.

ECS disaster recovery

If you use the ECS disaster recovery feature, you must take note of the limits on operating systems, platforms, databases, and applications. For more information, see Limits on ECS disaster recovery.

VMware disaster recovery

Before you restore a VMware VM to an ECS instance, read the following limits on the operating system and VMware platform of the ECS instance.
  • Windows Server
    Item Description
    System limits
    • You must verify the integrity of file systems.
    • You cannot modify critical system files.
    • You must make sure that the system disk has sufficient free space.
    • The configured system disk size must range from 40 GiB to 500 GiB.
    • You must make sure that the logon password for the administrator account meets the complexity requirements. The password must be 8 to 30 characters in length and must contain at least three of the following character types: uppercase letters, lowercase letters, digits, and special characters. The following special characters are supported: ( ) ` ~ ! @ # $ % ^ & * - _ + = | { } [ ] : ; ' < > , . ? /. The password cannot start with a forward slash (/).
    Unsupported items
    • You cannot install the QEMU Guest Agent in the system. If the QEMU Guest Agent is installed, some services that ECS requires may become unavailable.
    • The following operating system versions are not supported:
      • Windows XP
      • Windows 8
      • Windows 8.1
      • Windows 10
    • You cannot install Community Edition virtio drivers in Windows Server operating systems. If Community Edition virtio drivers are installed, you must remove the read-only property of the following files:
      • C:\Windows\System32\drivers\netkvm.sys
      • C:\Windows\System32\drivers\balloon.sys
      • C:\Windows\System32\drivers\vioser.sys
      • C:\Windows\System32\drivers\viostor.sys
      • C:\Windows\System32\drivers\pvpanic.sys
  • Linux
    Item Description
    System limits
    • You must verify the integrity of file systems.
    • You cannot modify critical system files such as /sbin, /bin, and /lib*.
      • You cannot modify /etc/issue*. Otherwise, the distribution of the operating system cannot be identified by ECS and the operating system cannot be created.
      • You cannot modify /boot/grub/menu.lst. Otherwise, the ECS instance cannot be started.
      • You cannot modify /etc/fstab. Otherwise, abnormal partitions cannot be loaded and the ECS instance cannot be started.
      • You cannot set /etc/shadow to read-only. Otherwise, the password file cannot be modified and the operating system cannot be created.
      • You cannot modify /etc/selinux/config to enable SELinux. Otherwise, the operating system cannot be started. If you need to enable SELinux, see Enable or disable SELinux.
    • You must make sure that the system disk has sufficient free space.
    • You must enable Dynamic Host Configuration Protocol (DHCP).
    • You must install Xen or KVM virtualization drivers. For more information, see Install the virtio driver.
    • You must install cloud-init to configure the hostname, NTP repositories, and YUM repositories. For more information, see Install cloud-init.
    • You must make sure that the logon password for the root account meets the complexity requirements. The password must be 8 to 30 characters in length and must contain three of the following character types: lowercase letters, uppercase letters, digits, and special characters. The following special characters are supported: ( ) ` ~ ! @ # $ % ^ & * - _ + = | { } [ ] : ; ' < > , . ? /.
    • The GRUB version of the operating system must meet the following requirements:
      • If the VM runs Linux, you must upgrade GRUB to V1.99 or later.
      • If the VM runs Linux of an earlier version, such as CentOS 5 or Red Hat 5, you must upgrade GRUB to V1.99 or later.
    Unsupported items
    • You can use only a single network interface to establish connections.
    • IPv6 addresses are not supported.
    • You cannot adjust system disk partitions. Only disks with a single root partition are supported.
    • You cannot install the QEMU Guest Agent in the system. If the QEMU Guest Agent is installed, some services that ECS requires may become unavailable.
    • You cannot create system disk partitions (the root partitions) across disks by using Logical Volume Manager (LVM). If you do so, the ECS instance may not be able to start.
  • VMware platform
    Item Description
    vCenter version Only vCenter Server 5.5, 6.0, 6.5, 6.7, and 7.0 are supported. A vCenter Server and an ESXi hypervisor must allow access from a migration gateway by using a fully qualified domain name (FQDN) or an IP address.
    Hardware version The hardware version of the VM must be version 10 (corresponding to ESXi 5.5) or later.

VMware VM migration

HBR provides non-intrusive, agentless, and full-copy migration for VMware VMs. HBR migrates data by using VMware VM snapshots and reading data from disks. These features allow you to migrate all the data that is stored on the disks of a VMware VM to the disks of an ECS instance. Before you migrate a VMware VM, read the following limits on the operating system and VMware platform of the ECS instance.

  • Windows Server
    Item Description
    System limits
    • You must verify the integrity of file systems.
    • You cannot modify critical system files.
    • You must make sure that the system disk has sufficient free space.
    • The configured system disk size must range from 40 GiB to 500 GiB.
    • You must make sure that the logon password for the administrator account meets the complexity requirements. The password must be 8 to 30 characters in length and must contain at least three of the following character types: uppercase letters, lowercase letters, digits, and special characters. The following special characters are supported: ( ) ` ~ ! @ # $ % ^ & * - _ + = | { } [ ] : ; ' < > , . ? /. The password cannot start with a forward slash (/).
    Unsupported items
    • You cannot install the QEMU Guest Agent in the system. If the QEMU Guest Agent is installed, some services that ECS requires may become unavailable.
    • The following operating system versions are not supported:
      • Windows XP
      • Windows 8
      • Windows 8.1
      • Windows 10
    • You cannot install Community Edition virtio drivers in Windows Server operating systems. If Community Edition virtio drivers are installed, you must remove the read-only property of the following files:
      • C:\Windows\System32\drivers\netkvm.sys
      • C:\Windows\System32\drivers\balloon.sys
      • C:\Windows\System32\drivers\vioser.sys
      • C:\Windows\System32\drivers\viostor.sys
      • C:\Windows\System32\drivers\pvpanic.sys
  • Linux
    Item Description
    System limits
    • You must verify the integrity of file systems.
    • You cannot modify critical system files such as /sbin, /bin, and /lib*.
      • You cannot modify /etc/issue*. Otherwise, the distribution of the operating system cannot be identified by ECS and the operating system cannot be created.
      • You cannot modify /boot/grub/menu.lst. Otherwise, the ECS instance cannot be started.
      • You cannot modify /etc/fstab. Otherwise, abnormal partitions cannot be loaded and the ECS instance cannot be started.
      • You cannot set /etc/shadow to read-only. Otherwise, the password file cannot be modified and the operating system cannot be created.
      • You cannot modify /etc/selinux/config to enable SELinux. Otherwise, the operating system cannot be started. If you need to enable SELinux, see Enable or disable SELinux.
    • You must make sure that the system disk has sufficient free space.
    • You must enable Dynamic Host Configuration Protocol (DHCP).
    • You must install Xen or KVM virtualization drivers. For more information, see Install the virtio driver.
    • You must install cloud-init to configure the hostname, NTP repositories, and YUM repositories. For more information, see Install cloud-init.
    • You must make sure that the logon password for the root account meets the complexity requirements. The password must be 8 to 30 characters in length and must contain three of the following character types: lowercase letters, uppercase letters, digits, and special characters. The following special characters are supported: ( ) ` ~ ! @ # $ % ^ & * - _ + = | { } [ ] : ; ' < > , . ? /.
    • The GRUB version of the operating system must meet the following requirements:
      • If the VM runs Linux, you must upgrade GRUB to V1.99 or later.
      • If the VM runs Linux of an earlier version, such as CentOS 5 or Red Hat 5, you must upgrade GRUB to V1.99 or later.
    Unsupported items
    • You can use only a single network interface to establish connections.
    • IPv6 addresses are not supported.
    • You cannot adjust system disk partitions. Only disks with a single root partition are supported.
    • You cannot install the QEMU Guest Agent in the system. If the QEMU Guest Agent is installed, some services that ECS requires may become unavailable.
    • You cannot create system disk partitions (the root partitions) across disks by using Logical Volume Manager (LVM). If you do so, the ECS instance may not be able to start.
  • VMware platform
    Item Description
    vCenter version Only vCenter Server 5.5, 6.0, 6.5, 6.7, and 7.0 are supported. A vCenter Server and an ESXi hypervisor must allow access from a migration gateway by using a fully qualified domain name (FQDN) or an IP address.
    Hardware version The hardware version of the VM must be version 10 (corresponding to ESXi 5.5) or later.