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Issue 09 (2021-06-21) Copyright © Huawei Technologies Co., Ltd. i Storage Disaster Recovery Service Product Introduction Contents Contents 1 SDRS Introduction................................................................................................................... 1 2 Product Advantages................................................................................................................ 3 3 Application Scenarios............................................................................................................. 5 4 Constraints................................................................................................................................ 6 5 Supported OSs..........................................................................................................................8 6 Relationships with Other Services.......................................................................................9 7 Pricing Details........................................................................................................................ 10 8 Basic Concepts........................................................................................................................12 8.1 SDRS Basic Concepts............................................................................................................................................................12 8.2 Region and AZ....................................................................................................................................................................... 15 9 Change History...................................................................................................................... 18 Issue 09 (2021-06-21) Copyright © Huawei Technologies Co., Ltd. ii Storage Disaster Recovery Service Product Introduction 1 SDRS Introduction 1 SDRS Introduction Storage DR Storage Disaster Recovery Service (SDRS) provides disaster recovery (DR) services for many cloud services, such as Elastic Cloud Server (ECS), Dedicated Distributed Storage Service (DSS) and Elastic Volume Service (EVS). SDRS uses multiple technologies, such as storage replication, data redundancy, and cache acceleration, to provide high data reliability and service continuity for users. SDRS protects service applications by replicating the server data and configurations to a DR site. It allows service applications to start at the DR site in the event that servers at the production site stop. This improves service availability and continuity. Figure 1-1 Storage DR DR and Backup Differences between DR and backup are as follows: ● DR is used to prevent impacts on the systems caused by natural disasters, such as fires and earthquakes. A production site and its DR site must be located with a certain secure distance. Backup is to prevent impacts on the systems caused by inappropriate manual operations, virus infection, and logic Issue 09 (2021-06-21) Copyright © Huawei Technologies Co., Ltd. 1 Storage Disaster Recovery Service Product Introduction 1 SDRS Introduction errors. It is used to restore the service system data. Usually, a system and its backup are deployed in the same data center. ● A DR system protects data but focuses more on protecting service continuity. A data backup system only ensures that data generated at different time points can be restored. Generally, the system performs the full backup for the first time, which takes a long period of time. The subsequent backup is incremental and can be completed within a short period of time. ● The highest DR standard is to implement zero RPO. You can set a maximum of 24 automatic backup policies at different time points in one day to restore data to different backup points. ● If a disaster occurs, such as earthquakes or fires, a DR system takes only several minutes to perform a failover, but a backup system takes several hours or even dozens of hours to restore the data. Issue 09 (2021-06-21) Copyright © Huawei Technologies Co., Ltd. 2 Storage Disaster Recovery Service Product Introduction 2 Product Advantages 2 Product Advantages SDRS has the following advantages: ● Convenient service recovery SDRS provides a management console. You can configure and manage server replication and perform a planned failover or failover. ● server replication You can establish a replication relationship between the production site and the DR site. ● Replication on demand You can replicate servers in an AZ to another AZ as required, thereby reducing the costs and complexity of maintaining another data center. ● Zero impact on applications Applications running on servers can be replicated, and the replication will not have any impact on the applications. ● RPO target SDRS provides continuous and synchronous replication for servers to ensure zero recovery point objective (RPO). ● Crash consistency Storage-based, real-time data synchronization keeps crash consistency for your data across two AZs. Specifically, application data might not be consistent during a failover, but disk data is always consistent. ● Seamless DR drills You can easily perform DR drills without affecting ongoing replication. ● Flexible failover You can perform a planned failover for an expected service interruption to prevent data loss, or perform a failover for unexpected failures to restore services quickly. ● Efficient network switchover SDRS simplifies program resource management during failovers, including reserving IP addresses and MAC addresses, all of which facilitates efficient network switchovers. ● Excellent performance for the price Issue 09 (2021-06-21) Copyright © Huawei Technologies Co., Ltd. 3 Storage Disaster Recovery Service Product Introduction 2 Product Advantages When services are running properly, servers at the DR site are stopped and thereby will not be billed. This greatly reduces the DR TCO. Issue 09 (2021-06-21) Copyright © Huawei Technologies Co., Ltd. 4 Storage Disaster Recovery Service Product Introduction 3 Application Scenarios 3 Application Scenarios Cross-AZ DR SDRS uses storage-layer synchronization and replication to provide cross-AZ DR to ensure data crash consistency and server-level protection with zero RPO. If a source AZ encounters a disaster (such as a fire or an earthquake) or a device fault (such as a software or hardware damage), replications running in the source AZ can quickly restore in the target AZ. For users of stateful applications, such as users of Microsoft Office 365, the data of these users must be stored on the disks of the servers with Microsoft Office 365 deployed. For such users, SDRS is suitable. DR Drill DR drills can be used to simulate fault scenarios, specify the emergency recovery solutions, and verify whether the solutions are applicable and effective. The existing services will not be affected during the DR drill. When a real fault occurs, you can use the solutions to rapidly restore services, enhancing service continuity. Issue 09 (2021-06-21) Copyright © Huawei Technologies Co., Ltd. 5 Storage Disaster Recovery Service Product Introduction 4 Constraints 4 Constraints Before using this service, you should be aware of the limitations listed in Table 4-1. Table 4-1 Constraints Constraint Description Computing Constraints on the instance type ● Kunpeng ECSs are not supported. ● x86 ECSs with GPU-accelerated and FPGA-accelerated types are not supported. Replication Constraints on servers ● The servers must be from different AZs of the same region. ● Bare Metal Server (BMS) is not supported. ● The following server types cannot be used to create protected instances: – Large Memory (Xen): This type of servers is bound to InfiniBand NICs. – Disk Intensive I (Xen): This type of servers has local disks. – Disk Intensive II (KVM): This type of ECSs has local disks. Constraints on disks ● Disks which have been used to create replication pairs do not support deletion or data rollback using snapshots. Storage Only servers using EVS or DSS can use this service. Application Storage-based synchronous replication ensures disk data consistency but cannot ensure application consistency. If your applications support crash consistency, the applications can run and be replicated on devices supporting