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OceanStor 18500, 18800, and 18800F Storage System V100R001C30 Remote Replication Feature Guide 09

This document describes the remote replication feature, in terms of the implementation principle, application scenario, configuration process, and reference information.
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Application Scenarios

Application Scenarios

The remote replication feature is used for data backup and DR. The typical application scenarios include central backup and DR, and 3DC.

Different remote replication modes apply to different application scenarios.
  • Synchronous remote replication applies to backup and DR scenarios where the primary site is very near to the secondary site, for example, in the same city (same data center or campus).
  • Asynchronous remote replication applies to backup and DR scenarios where the primary site is far from the secondary site (for example, cross countries or regions) or the network bandwidth is limited.
NOTE:

As for the asynchronous remote replication on an iSCSI network, you are advised to use a device such as a security gateway to encrypt links when adding the iSCSI links to ensure data transfer security among storage systems and prevent information leakage.

In a specific application scenario, determine the replication mode based on the distance and bandwidth between sites. Table 1-7 describes the typical application scenarios of the remote replication feature.
Table 1-7  Typical application scenarios of remote replication

Analysis Items

Central Backup and DR

3DC

Scenario characteristics

  • Backup data is managed centrally so that data analysis and data mining can be performed without affecting services.
  • When any of the service sites encounters a disaster, the central backup site can quickly take over services of the site and recover data, achieving unified service data management.
  • A remote replication mode can be selected for a service site flexibly based on the distance between the service site and the central backup site.
  • Three data centers (DCs) are deployed at two places. Real-time backup and remote backup are available concurrently.
  • Service data is backed up to the intra-city DR center in real time through a high-speed link.
  • After data in the production center is invalid, services are quickly switched to the intra-city DR center.
  • If a large-scale disaster damages the production center and DR center in the same city, the remote DR center can take over services and implement DR.

Remote replication mode

Synchronous remote replication or asynchronous remote replication

  • Intra-city: synchronous or asynchronous remote replication
  • Remote: asynchronous remote replication

Maximum distance

Synchronous remote replication: within 200 km

Asynchronous remote replication: no restriction

Synchronous remote replication: within 200 km

Asynchronous remote replication: no restriction

Central Backup and DR

In a central backup and DR scenario, service data distributed in different places is backed up to the same site for centralized management. Service data at multiple service sites is centrally backed up to and managed at the central backup site. When a disaster occurs at any service site, the central backup site can take over services from the service site and recover data. Figure 1-8 shows a central backup and DR scenario.
Figure 1-8  Central backup and DR

In the example shown in the previous figure, the remote replication feature can do the following things:
  • Collects data from n (a number) service sites to the central backup site, takes a snapshot of a secondary LUN, and maps the secondary LUN to a host. The snapshot can be used for data analysis and data mining.
  • Lets the central backup site to take over services when any service site (01 to n) encounters a disaster and switch services back to the service site when the site recovers.
  • Implements real-time backup (using the synchronous remote replication mode) from service site 01 to the central backup site, which is 500 m away from service site 01. Performs replication tasks (using the asynchronous remote replication mode) from service site 02 to the central backup site, which is 500 km away from service site 02.

3DC

3DC indicates that three DCs are deployed at two places in the DR solution. Three DCs consist of the production center, intra-city DR center, and remote DR center. The three DCs can be cascaded and interconnected in parallel mode based on different networks formed by storage systems in the three DCs.
  • Cascaded 3DC

    The production center (A), intra-city DR center (B), and remote DR center (C) are cascaded in A-B-C mode.

  • Parallel-connection 3DC

    The intra-city DR center (B) and remote DR center (C) concurrently serve as the DR centers for the production center (A). The three DCs are interconnected in A-B and A-C mode.

Figure 1-9 shows the cascaded 3DC in synchronous + asynchronous mode.
Figure 1-9  Cascaded 3DC in synchronous + asynchronous mode

The cascaded 3DC in synchronous + asynchronous mode meets the following service requirements:
  • Real-time backup and remote backup of data achieve robust reliability of critical service data and ensure that critical service data has two copies.
  • The cascaded 3DC has minor impact on the performance of the storage system in the production center and does not affect host services.
  • When the production center (A) encounters a disaster, the intra-city DR center (B) takes over services immediately and recovers data. If the secondary disaster damages the intra-city DR center (B), data in the remote DR center (C) is available.
Figure 1-10 shows the cascaded 3DC in asynchronous + asynchronous mode.
Figure 1-10  Cascaded 3DC in asynchronous + asynchronous mode

The cascaded 3DC in synchronous + asynchronous mode meets the following service requirements:
  • Real-time backup and remote backup of data achieve robust reliability of critical service data and ensure that critical service data has two copies.
  • The cascaded 3DC has minor impact on the performance of the storage system in the production center and does not affect host services.
  • When the production center (A) encounters a disaster, the intra-city DR center (B) takes over services immediately and recovers data. If the secondary disaster damages the intra-city DR center (B), data in the remote DR center (C) is available.
Figure 1-11 shows the parallel-connected 3DC in synchronous + asynchronous mode.
Figure 1-11  Parallel-connected 3DC in synchronous + asynchronous mode

The parallel-connected 3DC in synchronous + asynchronous mode meets the following service requirements:
  • Real-time backup and remote backup of data achieve robust reliability of critical service data and ensure that critical service data has two copies.
  • Data backup of the remote DR center (C) does not depend on the intra-city DR center (B). If the intra-city DR center (B) or remote DR center (C) fails, the production center (A) still has a backup site.
  • When the production center (A) encounters a disaster, the intra-city DR center (B) takes over services immediately and recovers data. If the secondary disaster damages the intra-city DR center (B), data in the remote DR center (C) is available.
Figure 1-12 shows the parallel-connected 3DC in asynchronous + asynchronous mode.
Figure 1-12  Parallel-connected 3DC in asynchronous + asynchronous mode

The parallel-connected 3DC in asynchronous + asynchronous mode meets the following service requirements:
  • Real-time backup and remote backup of data achieve robust reliability of critical service data and ensure that critical service data has two copies.
  • Data backup of the remote DR center (C) does not depend on the intra-city DR center (B). If the intra-city DR center (B) or remote DR center (C) fails, the production center (A) still has a backup site.
  • When the production center (A) encounters a disaster, the intra-city DR center (B) takes over services immediately and recovers data. If the secondary disaster damages the intra-city DR center (B), data in the remote DR center (C) is available.
NOTE:

The difference between 3DC in synchronous + asynchronous and asynchronous + asynchronous modes lies in the different data synchronization modes of the production center (A) and intra-city DR center (B). For the data synchronization mode used by the 3DC in synchronous + asynchronous mode, when data is concurrently written to the production center (A) and intra-city DR center (B), a message is displayed indicating that the synchronization succeeds. For the data synchronization mode used by the 3DC in asynchronous + asynchronous mode, when data is concurrently written to the production center (A), a message is displayed indicating that the synchronization succeeds.

ReplicationDirector

OceanStor ReplicationDirector is a piece of DR management software specifically designed for Huawei typical DR solutions. With application data consistency, snapshot, and remote replication, it provides a GUI-based and process-based platform for simple and rapid operation and monitoring.

Figure 1-13 illustrates how to use ReplicationDirector to deploy remote replication. Deploy the ReplicationDirector host in the DR center and install ReplicationDirector Server on the host. Install ReplicationDirector Agent on service hosts and DR hosts in the production center.

Figure 1-13  Using ReplicationDirector to deploy remote replication

Figure 1-14 and Figure 1-15 illustrate how to use ReplicationDirector to deploy 3DC. Deploy the ReplicationDirector host in DR centers 1 and 2 and install ReplicationDirector Server on the hosts. Install ReplicationDirector Agent on service hosts and DR hosts in the production center.

Figure 1-14  Using ReplicationDirector to deploy cascaded 3DC

Figure 1-15  Using ReplicationDirector to deploy parallel-connected 3DC

For details about how to use OceanStor ReplicationDirector, see the OceanStor ReplicationDirector User Guide.

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Updated: 2019-01-28

Document ID: EDOC1000077758

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