Understanding replication between Element and ONTAP

Starting with ONTAP 9.3, you can use SnapMirror to replicate Snapshot copies of an Element volume to an ONTAP destination. In the event of a disaster at the Element site, you can serve data to clients from the ONTAP system, then reactivate the Element source volume when service is restored.

Starting with ONTAP 9.4, you can replicate Snapshot copies of a LUN created on an ONTAP node back to an Element system. You might have created a LUN during an outage at the Element site, or you might be using a LUN to migrate data from ONTAP to Element software.

Types of data protection relationship

SnapMirror offers two types of data protection relationship. For each type, SnapMirror creates a Snapshot copy of the Element source volume before initializing or updating the relationship:

Default policies

The first time you invoke SnapMirror, it performs a baseline transfer from the source volume to the destination volume. The SnapMirror policy defines the contents of the baseline and any updates.

You can use a default or custom policy when you create a data protection relationship. The policy type determines which Snapshot copies to include and how many copies to retain.

The table below shows the default policies. Use the MirrorLatest policy to create a traditional DR relationship. Use the MirrorAndVault or Unified7year policy to create a unified replication relationship, in which DR and long-term retention are configured on the same destination volume.

Policy

Policy Type

Update behavior

MirrorLatest async-mirror Transfer the Snapshot copy created by SnapMirror.
MirrorAndVault mirror-vault Transfer the Snapshot copy created by SnapMirror and any less recent Snapshot copies made since the last update, provided they have SnapMirror labels daily or weekly.
Unified7year mirror-vault Transfer the Snapshot copy created by SnapMirror and any less recent Snapshot copies made since the last update, provided they have SnapMirror labels daily, weekly, or monthly.
Note: For complete background information on SnapMirror policies, including guidance on which policy to use, see the ONTAP Data Protection Power Guide.

Understanding SnapMirror labels

Every policy with the mirror-vault policy type must have a rule that specifies which Snapshot copies to replicate. The rule daily, for example, indicates that only Snapshot copies assigned the SnapMirror label daily should be replicated. You assign the SnapMirror label when you configure Element Snapshot copies.

Replication from an Element source cluster to an ONTAP destination cluster

You can use SnapMirror to replicate Snapshot copies of an Element volume to an ONTAP destination system. In the event of a disaster at the Element site, you can serve data to clients from the ONTAP system, then reactivate the Element source volume when service is restored.

An Element volume is roughly equivalent to an ONTAP LUN. SnapMirror creates a LUN with the name of the Element volume when a data protection relationship between Element software and ONTAP is initialized. SnapMirror replicates data to an existing LUN if the LUN meets the requirements for Element to ONTAP replication.

Replication rules are as follows:

Replication from an ONTAP source cluster to an Element destination cluster

Starting with ONTAP 9.4, you can replicate Snapshot copies of a LUN created on an ONTAP system back to an Element volume:

Replication rules are as follows:

Prerequisites

You must have completed the following tasks before configuring a data protection relationship between Element and ONTAP:

Support details

The following table shows support details for Element to ONTAP backup.

Resource or feature Support details
SnapMirror
  • The SnapMirror restore feature is not supported.
  • The MirrorAllSnapshots and XDPDefault policies are not supported.
  • The vault policy type is not supported.
  • The system-defined rule all_source_snapshots is not supported.
  • The mirror-vault policy type is supported only for replication from Element software to ONTAP. Use async-mirror for replication from ONTAP to Element software.
  • The -schedule and -prefix options for snapmirror policy add-rule are not supported.
  • The -preserve and -quick-resync options for snapmirror resync are not supported.
  • Storage efficiency is not preserved.
  • Fan-out and cascade data protection deployments are not supported.
ONTAP
  • ONTAP Select is supported starting with ONTAP 9.4 and Element 10.3.
  • Cloud Volumes ONTAP is supported starting with ONTAP 9.5 and Element 11.0.
Element
  • Volume size limit is 8 TiB.
  • Volume block size must be 512 bytes. A 4K byte block size is not supported.
  • Volume size must be a multiple of 1 MiB.
  • Volume attributes are not preserved.
  • Maximum number of Snapshot copies to be replicated is 30.
Network
  • A single TCP connection is allowed per transfer.
  • The Element node must be specified as an IP address. DNS hostname lookup is not supported.
  • IPspaces are not supported.
SnapLock SnapLock volumes are not supported.
FlexGroup FlexGroup volumes are not supported.
SVM DR ONTAP volumes in an SVM DR configuration are not supported.
MetroCluster ONTAP volumes in a MetroCluster configuration are not supported.