Cloud Backup:Limits

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 a Cloud Backup 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. For more information, see Connect a VPC to a data center in single-tunnel mode.

• Cloud Backup supports a limited number of database versions, operating systems, and backup features. For more information, see Database backup.

File backup

• Cloud 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 Cloud Backup attempts to back up a file on which Cloud Backup 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 Cloud Backup attempts to back up a file on which Cloud Backup 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

• The vCenter Server version of the vSphere Web Client must be 5.5, 6.0, 6.5, 6.7, or 7.0.

• 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.

• The virtual machine (VM) that you want to back up cannot have snapshots. 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 Small Computer System Interface (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. For more information, see Back up an SAP HANA instance.

• Backint supports the following SAP HANA versions:

  • Backint supports SAP HANA 1.0 SPS 09 (revision 94) and later. Backint does not support single-container systems in SAP HANA 1.0.

  • Backint supports multitenant database containers (MDCs) in SAP HANA 2.0 SPS 01 and later.

• For more information, see Overview of the SAP HANA backup feature and FAQ about SAP HANA backup.

NAS backup

NAS backup does not support access control lists (ACLs) for Server Message Block (SMB) file systems. For more information, see Back up an Apsara File Storage NAS file system.

OSS backup

• To improve the performance of incremental backup, Cloud Backup uses the latest OSS inventory list that is generated 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, Cloud Backup 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

VMware VM migration

Cloud Backup provides non-intrusive, agentless, and full-copy migration for VMware VMs. Cloud Backup 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 (/).
  Supported operating systems	Windows Server 2012 Windows Server 2016
  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 Windows 11 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 requirement: If the VM runs Linux, you must upgrade GRUB to V1.99 or later.
  Supported operating systems	CentOS 6, 7, and 8 Major Ubuntu versions Debian 4, 5, 6, 7, 8, 9, and 10 SUSE 10, 11, 12, and 15 openSUSE FreeBSD 11 and 12 RHEL 4, 5, 6, 7, and 8
  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.