What Are RPO and RTO?

Recovery Point Objective (RPO): the maximum data loss amount tolerated by the system.

• SDRS asynchronous replication is based on the continuous asynchronous replication on the host side. Normally, the RPO is not zero (RPO < 1 minute).

  This RPO can be achieved when the following conditions are met:

  1. Actual network bandwidth > Changed data volume per minute in peak hours/1 minute. Minimum bandwidth: 10 Mbit/s
  2. Network latency ≤ 100 ms; packet loss rate < 0.1%
  3. If the initial synchronization or differential data synchronization is not complete for a protected instance, this RPO is not guaranteed.
  4. During a planned switchover, ensure that the services and OS data in the cache has been flushed to disks.

Recovery Time Objective (RTO): the maximum service interruption duration tolerated by the system. It refers to the requirement for the recovery duration of an information system failure or service function failure caused by a disaster.

• In SDRS replication, RTO refers to the period from the time when you perform a planned or an unplanned failover to the time when ECSs are started on Huawei Cloud. Note that this period does not include the time that you spent on manual configuration, operations, network configuration, and script execution to try to start services. Normally, the RTO is not zero (RTO < 30 minutes).
  This RTO can be achieved when the following conditions are met:

  1. A failover is performed after the initial synchronization is complete.
  2. Your account has sufficient resource quotas, including ECS, EVS, and VPC quotas.
  3. The RTO of SDRS asynchronous replication does not include the time that you spent on manual configuration and service configuration.

Figure 1 RPO and RTO