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Requirements and considerations for using cross-region replication

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This article describes requirements and considerations about using the volume cross-region replication functionality of Azure NetApp Files.

Requirements and considerations

  • Azure NetApp Files replication is only available in certain fixed region pairs. See Supported region pairs.
  • SMB volumes are supported along with NFS volumes. Replicating SMB volumes requires an Active Directory connection in the source and destination NetApp accounts. The destination AD connection must have access to the DNS servers or AD DS Domain Controllers that are reachable from the delegated subnet in the destination region. For more information, see Requirements for Active Directory connections.
  • The destination account must be in a different region from the source volume region. You can also select an existing NetApp account in a different region.
  • The replication destination volume is read-only until you fail over to the destination region to enable the destination volume for read and write.

    Important

    Failover is a manual process. When you need to activate the destination volume (for example, when you want to fail over to the destination region), you need to break replication peering then mount the destination volume. For more information, see fail over to the destination volume

    Important

    A volume with an active backup policy enabled can't be the destination volume in a reverse resync operation. You must suspend the backup policy on the volume prior to starting the reverse resync then resume when the reverse resync completes.

  • Azure NetApp Files replication doesn't currently support multiple subscriptions; all replications must be performed under a single subscription.
  • See resource limits for the maximum number of cross-region replication destination volumes. You can open a support ticket to request a limit increase in the default quota of replication destination volumes (per subscription in a region).
  • There can be a delay up to five minutes for the interface to reflect a newly added snapshot on the source volume.
  • Cascading and fan in/out topologies aren't supported.
  • After you set up cross-region replication, the replication process creates SnapMirror snapshots to provide references between the source volume and the destination volume. SnapMirror snapshots are cycled automatically when a new one is created for every incremental transfer. You can't delete SnapMirror snapshots until replication relationship and volume is deleted.
  • You can't mount a dual-protocol volume until you authorize replication from the source volume and the initial transfer happens.
  • You can delete manual snapshots on the source volume of a replication relationship when the replication relationship is active or broken, and also after the replication relationship is deleted. You can't delete manual snapshots for the destination volume until the replication relationship is broken.
  • You can revert a source or destination volume of a cross-region replication to a snapshot, provided the snapshot is newer than the most recent SnapMirror snapshot. Snapshots older than the SnapMirror snapshot can't be used for a volume revert operation. For more information, see Revert a volume using snapshot revert.
  • Data replication volumes support customer-managed keys.
  • If you are copying large data sets into a volume that has cross-region replication enabled and you have spare capacity in the capacity pool, you should set the replication interval to 10 minutes, increase the volume size to allow for the changes to be stored, and temporarily disable replication.
  • If you use the cool access feature, see Manage Azure NetApp Files storage with cool access for more considerations.
  • Large volumes are supported with cross-region replication only with an hourly or daily replication schedule.
  • If the volume's size exceeds 95% utilization, there's a risk that replication to the destination volume can fail depending on the rate of data changes.

Large volumes configuration

Large volumes are supported with cross-region replication. You must first register for the large volumes feature then register to use large volumes with cross-region replication:

Note

Cross-zone and cross-region replication use the same Azure Feature Exposure Control (AFEC) name of ANFLargeVolumesCRR. If you've registered for cross-zone replication, the registration also works for cross-region replication.

  1. Register the feature by running the following commands:

    Register-AzProviderFeature -ProviderNamespace Microsoft.NetApp -FeatureName ANFLargeVolumesCRR

  2. Check the status of the feature registration:

    Note

    The RegistrationState may be in the Registering state for up to 60 minutes before changing to Registered. Wait until the status is Registered before continuing.

    Get-AzProviderFeature -ProviderNamespace Microsoft.NetApp -FeatureName ANFLargeVolumesCRR

You can also use Azure CLI commands az feature register and az feature show to register the feature and display the registration status.

Next steps