Understanding SnapMirror SVM replication
You can use SnapMirror to create a data protection relationship between SVMs. In this type of data protection relationship, all or part of the SVM's configuration, from NFS exports and SMB shares to RBAC, is replicated, as well as the data in the volumes that the SVM owns.
Supported relationship types
Only data-serving SVM can be replicated. The following data protection relationship types are supported:
- SnapMirror DR, in which the destination typically contains only the Snapshot copies currently on the source SVM.
Details about these relationship types can be found here: Understanding SnapMirror volume replication.
The policy type of the replication policy determines the type of relationship it supports. The following table shows the available policy types.
Policy type | Relationship type |
|---|---|
| async-mirror | SnapMirror DR |
| mirror-vault | Unified replication |
XDP replaces DP as the SVM replication default in ONTAP 9.5
Starting with ONTAP 9.5, SVM data protection relationships default to XDP mode.
Existing relationships are not affected by the new default. If a relationship is already of type DP, it will continue to be of type DP. The following table shows the behavior you can expect.
If you specify... | The type is... | The default policy (if you do not specify a policy) is... |
|---|---|---|
| DP | XDP | MirrorAllSnapshots (SnapMirror DR) |
| Nothing | XDP | MirrorAllSnapshots (SnapMirror DR) |
| XDP | XDP | MirrorAndVault (Unified replication) |
Details about the changes in the default can be found here: XDP replaces DP as the SnapMirror default.
How SVM configurations are replicated
The content of an SVM replication relationship is determined by the interaction of the following fields:
The -identity-preserve true option of the snapmirror create command replicates the entire SVM configuration.
The -identity-preserve false option replicates only the volumes and authentication and authorization configurations of the SVM, and the protocol and name service settings listed in Configurations replicated in SVM DR relationships.
The -discard-configs network option of the snapmirror policy create command excludes LIFs and related network settings from SVM replication, for use in cases where the source and destination SVMs are in different subnets.
The -vserver-dr-protection unprotected option of the volume modify command excludes the specified volume from SVM replication.
Otherwise, SVM replication is almost identical to volume replication. You can use virtually the same workflow for SVM replication as you use for volume replication.
Support details
The following table shows support details for SnapMirror SVM replication.
| Resource or feature | Support details |
|---|---|
| Relationship types |
|
| Replication scope | Intercluster only. You cannot replicate SVMs in the same cluster. |
| Version-independence | Not supported. |
| Deployment types |
|
| Volume encryption |
|
| FabricPool | Starting with ONTAP 9.6, SnapMirror SVM replication is supported with FabricPools. |
| MetroCluster | Starting with ONTAP 9.5, SnapMirror SVM replication is supported on MetroCluster configurations.
|
Configurations replicated in SVM DR relationships
The following table shows the interaction of the snapmirror create -identity-preserve option and the snapmirror policy create -discard-configs network option:
| Configuration replicated | ‑identity‑preserve true | ‑identity‑preserve false | ||
|---|---|---|---|---|
| Policy without -discard-configs network set | Policy with -discard-configs network set | |||
| Network | NAS LIFs | Yes | No | No |
| LIF Kerberos configuration | Yes | No | No | |
| SAN LIFs | No | No | No | |
| Firewall policies | Yes | Yes | No | |
| Routes | Yes | No | No | |
| Broadcast domain | No | No | No | |
| Subnet | No | No | No | |
| IPspace | No | No | No | |
| CIFS | CIFS server | Yes | Yes | No |
| Local groups and local user | Yes | Yes | Yes | |
| Privilege | Yes | Yes | Yes | |
| Shadow copy | Yes | Yes | Yes | |
| BranchCache | Yes | Yes | Yes | |
| Server options | Yes | Yes | Yes | |
| Server security | Yes | Yes | No | |
| Home directory, share | Yes | Yes | Yes | |
| Symlink | Yes | Yes | Yes | |
| Fpolicy policy, Fsecurity policy, and Fsecurity NTFS | Yes | Yes | Yes | |
| Name mapping and group mapping | Yes | Yes | Yes | |
| Audit information | Yes | Yes | Yes | |
| NFS | Export policies | Yes | Yes | No |
| Export policy rules | Yes | Yes | No | |
| NFS server | Yes | Yes | No | |
| RBAC | Security certificates | Yes | Yes | No |
| Login user, public key, role, and role configuration | Yes | Yes | Yes | |
| SSL | Yes | Yes | No | |
| Name services | DNS and DNS hosts | Yes | Yes | No |
| Linux user and Linux group | Yes | Yes | Yes | |
| Kerberos realm and Kerberos keyblocks | Yes | Yes | No | |
| LDAP and LDAP client | Yes | Yes | No | |
| Netgroup | Yes | Yes | No | |
| NIS | Yes | Yes | No | |
| Web and web access | Yes | Yes | No | |
| Volume | Object | Yes | Yes | Yes |
| Snapshot copies, Snapshot policy, and autodelete policy | Yes | Yes | Yes | |
| Efficiency policy | Yes | Yes | Yes | |
| Quota policy and quota policy rule | Yes | Yes | Yes | |
| Recovery queue | Yes | Yes | Yes | |
| Root volume | Namespace | Yes | Yes | Yes |
| User data | No | No | No | |
| Qtrees | No | No | No | |
| Quotas | No | No | No | |
| File-level QoS | No | No | No | |
| Attributes: state of the root volume, space guarantee, size, autosize, and total number of files | No | No | No | |
| Storage QoS | QoS policy group | Yes | Yes | Yes |
| Fibre Channel (FC) | No | No | No | |
| iSCSI | No | No | No | |
| LUNs | Object | Yes | Yes | Yes |
| igroups | No | No | No | |
| portsets | No | No | No | |
| Serial numbers | No | No | No | |
| SNMP | v3 users | Yes | Yes | No |