Getting started with policy-based replication
Policy-based replication provides simplified configuration and management of asynchronous replication between two systems.
- Uses volume groups instead of consistency groups. With volume groups, all volumes are replicated based on the assigned policy.
- Simplifies administration by removing the need to manage relationships and change volumes.
- Automatically manages provisioning on the remote system.
- Supports easier visualization of replication during a site failover.
- Automatically notifies you when the recovery point objective (RPO) is exceeded.
- Easy-to-understand status and alerts on the overall health of replication.
- IBM® SAN Volume Controller
- IBM Storage FlashSystem 9500
- IBM Storage FlashSystem 9200
- IBM Storage FlashSystem 9100
- IBM Storage FlashSystem 7300
- IBM Storage FlashSystem 7200
- IBM Storage FlashSystem 5200 (requires a minimum of 128 GB memory in each node canister)
- IBM Storage Virtualize for Public Cloud
To learn more about concepts and objects that are related to the policy-based replication, see the Overview topics and Volume groups.
Prerequisites
Before you can implement policy-based replication, determine your current recovery point objectives, applications requirements, and verify your networking configuration. For more information, see Planning policy-based replication.
Configuring policy-based replication
As part of policy-based replication, the management GUI provides an interactive checklist to guide you through all the configuration steps. For example, the checklist provides links to launch directly to the remote system to complete the partnership and pool link configuration steps, and indicates when each step is completed. You can use this interactive checklist when you are configuring policy-based replication for the first time.
- Creating partnership for replication
- For policy-based replication, a two-site partnership must be configured between the production and recovery systems. The partnership establishes a secure connection between systems that use either Fibre Channel or IP protocols. To configure partnership, see Creating partnership for replication.
- Creating provisioning policies (optional)
- A provisioning policy is an entity that defines a set of rules for allocating capacity from a pool. Any volumes that are created in the pool adopt the capacity-saving methods that are defined in the provisioning policy. A provisioning policy simplifies the volume provisioning process by specifying capacity savings methods per pool.. For more information, see Creating provisioning policy and assigning to pools.
- Creating a linked pool
- With policy-based replication, storage pool links define which pool on the recovery system stores the recovery copy of the volume, based on the pool where the production volume exists. The pools on the recovery system require links to the pools on the production system. Links are required on any pool that contains volumes that use policy-based replication. Policy-based replication requires at least one pool to be linked on each system. When linking pools on a stretched topology system, only the pools that are in site 1 are required to be linked. For more information, see Creating linked pools.
- Creating replication policies
- A replication policy is defined between two systems in a partnership that supports policy-based replication. The partnership must be fully-configured and each system must be connected. Each replication policy identifies a single I/O group on each system. To replicate volume groups from multiple I/O groups, you will need to create another replication policy. A maximum of two I/O groups in each system can replicate using replication policies. You can use the management GUI interface and command-line interface (CLI) for creating replication policies. To configure replication policy, see Creating replication policies.
- Creating volume group and assign replication policy
- Policy-based replication uses volume groups and replication policies to deploy and manage replications. After you create a replication policy, you need to create a volume group and assign it to the replication policy. When you add source volumes to the volume group on a production system, they are replicated together to the recovery system to ensure consistent replication. In addition, recovery copies of volume groups are immutable. Policy-based replication significantly simplifies configuring, managing, and monitoring replication between two systems. For more information, see Creating a volume group and assigning replication policy.
If you currently use Global Mirror or Global Mirror with change volumes configurations to replicate data between two systems, it is possible to convert to policy-based replication from these configurations. Other remote copy functions, like 3-site partnerships, nondisruptive volume migration, and Metro Mirror cannot be converted to policy-based replication without first converting any relationships to Global Mirror.
Managing policy-based replication
Monitoring and troubleshooting policy-based replication
Policy-based replication supports simplified monitoring of replication status and RPO and interactive error resolution through directed maintenance procedures (DMP). For more information, see the following topics: