Deployment of SnapMirror

A basic deployment of SnapMirror consists of source volumes and qtrees, and destination volumes and qtrees.

Source volumes or qtrees: In a SnapMirror configuration, source volumes and qtrees are the data objects that need to be replicated. Normally, the users of storage can access and write to source volumes and qtrees.

Figure 1. Basic SnapMirror deployment

• Supported SnapMirror configurations
  You can use SnapMirror to replicate both tranditional and FlexVol volumes. However, there are certain configurations that are not supported for replication.
• SnapMirror deployment variations
  There are several variations possible while deploying SnapMirror. These variations allow you to customize the solution to suit your requirements.
• Maximum number of concurrent replication operations
  A volume SnapMirror replication, qtree SnapMirror replication, or SnapVault replication consists of two operations, one operation on the source side of the transfer and the other on the destination side. Therefore, if a storage system is the source of one replication and the destination of another replication, it uses two replication operations. Likewise, if a storage system is the source and destination of the same replication, it uses two replication operations.
• Migration from traditional volumes to FlexVol volumes
  You can use only qtree SnapMirror to migrate data from traditional volumes to FlexVol volumes, if you use SnapMirror for this type of migration. You cannot use volume SnapMirror for this purpose because it cannot replicate to a different type of volume.
• Symmetrical disk geometry
  When replicating data with FlexVol volumes, disk geometry is not an issue, unlike in the case of traditional volumes.
• SnapMirror setup commands and configuration files
  There are several commands and configuration files that enable you to set up SnapMirror replication.
• Considerations for the use of SnapMirror
  Remember the following when you plan to use SnapMirror for replication.
• Considerations before using synchronous SnapMirror
  Remember the following when you plan to use SnapMirror for synchronous replication.
• Setting up a basic SnapMirror operation
  You must have the proper licenses installed and source storage systems must know where they are replicating data before replicating data.
• SnapMirror over multiple paths
  You might want more than one physical path for a SnapMirror relationship. SnapMirror supports up to two paths for a particular SnapMirror relationship.
• Enabling SnapMirror by entering license codes
  Before any SnapMirror replication process can begin, the SnapMirror feature must be licensed and enabled on the storage system.
• Initialization of a SnapMirror destination
  You must use the snapmirror initialize command to perform a complete (baseline) transfer of information whenever you start a SnapMirror source-destination relationship for the first time. This process is known as initializing a destination.
• Setting a maximum transfer rate for all transfers
  Setting a maximum transfer rate for all transfers enables you to limit the total bandwidth used by all transfers at any time. To set a maximum transfer rate for all transfers, Data ONTAP allows you to set a maximum rate for transfers coming into a storage system and to set a maximum rate for transfers going out of a storage system.
• Data replication from one destination to another in a series (cascading)
  You can replicate data from a SnapMirror destination to another storage system using SnapMirror. Therefore, a storage system that is a destination for one SnapMirror relationship, can act as the source for another SnapMirror relationship. This is useful when you need to copy data from one site to many sites.
• SnapMirror source to tape to destination scenario
  In this scenario, you want to establish a SnapMirror relationship between a source system and a destination system over a low-bandwidth connection. Incremental Snapshot mirroring from the source to the destination over the low bandwidth connection is feasible, but the initial base Snapshot mirroring is not.