Configuring asymmetric protection using SnapMirror active sync involves selecting LUNs on the ONTAP source cluster and adding them to a consistency group.

Before you begin

You must have a SnapMirror synchronous license.
You must be a cluster or storage VM administrator.
All constituent volumes in a consistency group must be in a single storage VM (SVM).
- LUNs can reside on different volumes.
The source and destination cluster cannot be the same.
You cannot establish SnapMirror active sync consistency group relationships across ASA clusters and non-ASA clusters.
The default IPspace is required by SnapMirror active sync for cluster peer relationships. Custom IPspace is not supported.
The name of the consistency group must be unique.
The volumes on the secondary (destination) cluster must be type DP.
The primary and the secondary SVMs must be in a peered relationship.

Steps

You can configure a consistency group using the ONTAP CLI or ONTAP System Manager.

Beginning in ONTAP 9.10.1, ONTAP offers a consistency group endpoint and menu in ONTAP System Manager, offering additional management utilities. If you are using ONTAP 9.10.1 or later, see Configure a consistency group then configure protection to create an SnapMirror active sync relationship.

From ONTAP 9.8 through 9.14.1, SnapMirror active sync is referred to as SnapMirror Business Continuity (SM-BC).

ONTAP System Manager

On the primary cluster, navigate to Protection > Overview > Protect for Business Continuity > Protect LUNs.
Select the LUNs you want to protect and add them to a protection group.
Select the destination cluster and SVM.
Initialize relationship is selected by default. Click Save to begin protection.
Go to Dashboard > Performance to verify IOPS activity for the LUNs.
On the destination cluster, use ONTAP System Manager to verify that the protection for business continuity relationship is in sync: Protection > Relationships.

CLI

Create a consistency group relationship from the destination cluster.
destination::> snapmirror create -source-path source-path -destination-path destination-path -cg-item-mappings volume-paths -policy policy-name

You can map up to 12 constituent volumes using the cg-item-mappings parameter on the snapmirror create command.

The following example creates two consistency groups: cg_src_ on the source with `vol1 and vol2 and a mirrored destination consistency group, cg_dst.

destination::> snapmirror create -source-path vs1_src:/cg/cg_src -destination-path vs1_dst:/cg/cg_dst -cg-item-mappings vol_src1:@vol_dst1,vol_src2:@vol_dst2 -policy AutomatedFailOver
From the destination cluster, initialize the consistency group.

destination::>snapmirror initialize -destination-path destination-consistency-group
Confirm that the initialization operation completed successfully. The status should be InSync.

snapmirror show
On each cluster, create an igroup so you can map LUNs to the initiator on the application host.
lun igroup create -igroup name -protocol fcp|iscsi -ostype os -initiator initiator_name
On each cluster, map LUNs to the igroup:

lun map -path path_name -igroup igroup_name
Verify the LUN mapping completed successfully with the lun map command. Then, you can discover the new LUNs on the application host.

Configure symmetric active/active protection

You can establish symmetric protection using ONTAP System Manager or the ONTAP CLI. In both interfaces, there are different steps for uniform and non-uniform configurations.

Before you begin

Both clusters must be running ONTAP 9.15.1 or later.
Symmetric active/active configurations require the AutomatedFailoverDuplex protection policy. Alternately, you can create a custom SnapMirror policy provided the -type is automated-failover-duplex.

Example 1. Steps

ONTAP System Manager

Steps for a uniform configuration

On the primary site, create a consistency group using new LUNs.
1. When creating the consistency group, specify host initiators to create igroups.
2. Select the checkbox to Enable SnapMirror then choose the AutomatedFailoverDuplex policy.
3. In the dialog box that appears, select the Replicate initiator groups checkbox to replicate igroups. In Edit proximal settings, set proximal SVMs for your hosts.
4. Select Save.

Steps for a non-uniform configuration

On the primary site, create a consistency group using new LUNs.
1. When creating the consistency group, specify host initiators to create igroups.
2. Select the checkbox to Enable SnapMirror then choose the AutomatedFailoverDuplex policy.
3. Select Save to create the LUNs, consistency group, igroup, SnapMirror relationship, and igroup mapping.
On the secondary site, create an igroup and map the LUNs.
1. Navigate to Hosts > SAN Initiator Groups.
2. Select +Add to create a new igroup.
3. Provide a Name, select the Host Operating System, then choose Initiator Group Members.
4. Select Save.
Map the new igroup to the destination LUNs.
1. Navigate to Storage > LUNs.
2. Select all the LUNs to map to the igroup.
3. Select More then Map to Initiator Groups.

CLI

Steps for a uniform configuration

Create a new SnapMirror relationship grouping all the volumes in the application. Ensure you designate the AutomatedFailOverDuplex policy to establish bidirectional sync replication.

snapmirror create -source-path source_path -destination-path destination_path -cg-item-mappings source_volume:@destination_volume -policy AutomatedFailOverDuplex
Confirm the operation has succeeded by waiting for the Mirrored State to show as SnapMirrored and the Relationship Status as Insync.

snapmirror show -destination-path destination_path
On your host, configure host connectivity with access to each cluster according to your needs.
Establish the igroup configuration. Set the preferred paths for initiators on the local cluster. Specify the option to replicate the configuration to the peer cluster inverse affinity.

SiteA::> igroup create -vserver svm_name -igroup igroup_name -replication-peer peer_svm_name -initiators host -proximal-vserver local

SiteA::> igroup add -vserver svm_name -igroup igroup_name -initiators host -proximal-vserver peer_svm
From the host, discover the paths and verify the hosts have an active/optimized path to the storage LUN from the preferred cluster.
Deploy the application and distribute the VM workloads across clusters to achieve the required load balancing.

Steps for a non-uniform configuration

Create a new SnapMirror relationship grouping all the volumes in the application. Ensure you designate the `AutomatedFailOverDuplex`" policy to establish bidirectional sync replication.

snapmirror create -source-path source_path -destination-path destination_path -cg-item-mappings source_volume:@destination_volume -policy AutomatedFailOverDuplex
Confirm the operation has succeeded by waiting for the Mirrored State to show as SnapMirrored and the Relationship Status as Insync.

snapmirror show -destination-path destination_path
On your host, configure host connectivity with access to each cluster according to your needs.
Establish the igroup configurations on both the source and destination clusters.

# primary site SiteA::> igroup create -vserver svm_name -igroup igroup_name -initiators host_1_name

# secondary site SiteB::> igroup create -vserver svm_name -igroup igroup_name -initiators host_2_name
From the host, discover the paths and verify the hosts have an active/optimized path to the storage LUN from the preferred cluster.
Deploy the application and distribute the VM workloads across clusters to achieve the required load balancing.