Remember the following when you plan to use SnapMirror for synchronous replication.
For synchronous SnapMirror, the disks on both the source and destination storage systems should be of the same type—either ATA on both sides or Fibre Channel on both sides. The combination of the two types of disks in any configuration is not supported for use with synchronous SnapMirror.
| Type of volume | Data ONTAP version |
|---|---|
| Traditional volumes | 7.2 or later |
| FlexVol volumes | 7.2.2 or later |
You can choose the data to be synchronously replicated. For example, you can synchronously replicate database data and asynchronously replicate home directories. If the home directories contain important log data, you can use the synchronous SnapMirror option to replicate it. For more details, see the na_snapmirror.conf(5) man page.
The type of system and the disk configuration on the destination storage system affects the performance of the source storage system. Therefore, the destination storage system should have the bandwidth required for the increased traffic and for message logging. The NVLOG files are stored in the parent aggregate of the volume being replicated.
The network transport should be optimized for SnapMirror replication. You must use a dedicated, high-bandwidth, low-latency network between the source and destination storage systems. Synchronous SnapMirror can support traffic over Fibre Channel and IP transports. SnapMirror also allows multipathing, enabling you to either balance the load between two paths or to reserve the second path for failover. For optimizing performance, you can use the best route available between the source and destination storage systems, and you can restrict the route to the traffic between the two systems.
Keep well below the maximum number of Snapshot copies. Synchronous SnapMirror needs three Snapshot copies to get into synchronization. Therefore, limit the combined total of Snapshot copies retained on any one volume to 252 or fewer.