This topic describes the limits of the Elastic Compute Service (ECS) disaster recovery feature on operating systems, platforms, databases, and applications.

Operating systems

The following table describes the operating systems that support ECS disaster recovery.
Operating system Version
Windows Server 2008 R2, 2012, 2012 R2, and 2016
Linux
Notice You must make sure that the /boot partition and the / partition reside on the same disk. If the partitions do not reside on the same disk, move the partitions to the same disk, and then register the ECS instance for which you want to enable ECS disaster recovery.
  • Red Hat Enterprise Linux 7.0~7.9
  • Red Hat Enterprise Linux 6.0~6.10
  • CentOS 7.0~7.9
  • CentOS 6.0~6.10
    Note ECS disaster recovery is available for ECS instances that run 64-bit CentOS 6.x operating systems. If you want to implement disaster recovery for ECS instances that run 32-bit CentOS 6.x operating systems, submit a ticket.
  • SUSE Linux Enterprise Server 12.0~12.3
    Notice
    • ECS disaster recovery is available for ECS instances that run 64-bit SUSE Linux Enterprise Server 12.x operating systems. If you want to implement disaster recovery for ECS instances that run 32-bit SUSE Linux Enterprise Server 12.x operating systems, submit a ticket.
    • If SUSE Linux Enterprise Server 12.1 runs on a VMware virtual machine, a black screen appears after you restart the virtual machine. The black screen is caused by operating system errors, but not by ECS disaster recovery.
  • Alibaba Cloud Linux 2.1903 LTS 64-bit
    The following kernel versions of Alibaba Cloud Linux 2.1903 LTS 64-bit are supported:
    • 4.19.91-25.1.al7.x86_64
    • 4.19.91-24.1.al7.x86_64
    • 4.19.91-23.al7.x86_64
    • 4.19.91-22.2.al7.x86_64
    Notice If you need to use other kernel versions, submit a ticket.

Platforms

ECS disaster recovery is implemented based on the disk-level data replication technology and is independent of the underlying platform. The following table describes the platforms that support ECS disaster recovery. If you have questions, submit a ticket.

Platform Version
Physical machine Full support
vSphere 5.5, 6.0, 6.5, 6.7, and 7.0

Databases and applications

You can apply the replication technology of ECS disaster recovery to all types of databases and applications.

In most cases, automated scripts are required for various applications to ensure consistency among updates. You can use the tools and scripts that are provided by Alibaba Cloud to implement ECS disaster recovery. This ensures smooth recovery of applications.

Other limits

ECS disaster recovery also has the following limits:

  • If the size of a physical volume where the system disk of an ECS instance resides exceeds 2 TB, you cannot perform a full restoration on the ECS instance.
  • A single physical volume of a data disk cannot exceed 32 TB.
  • Disk write limits:
    • Linux

      If the average IO size is 4 KB, the maximum disk write speed is about 10 MB/s. If the average IO size is 64 KB, the maximum disk write speed is about 30 MB/s.

    • Windows

      The maximum disk write speed is 10 MB/s.

    If the IO size is smaller or the disk write volume is larger, the Recovery Point Objective (RPO) is not affected, but the Recovery Time Objective (RTO) is prolonged.

    When you perform cross-region disaster recovery, the total throughput supported by a single site pair is 400 Mbit/s. If the data volume exceeds this limit, both the RPO and RTO may be prolonged. When you design a disaster recovery solution, you must evaluate the business situation of protected servers and estimate the amount of data written to disks.