Create and initializing load-sharing mirror relationships

11/30/2023 Contributors

You should create a load-sharing mirror (LSM) for each SVM root volume that serves NAS data in the cluster. For clusters consisting of two or more HA pairs, you should consider load-sharing mirrors of SVM root volumes to ensure the namespace remains accessible to clients in the event that both nodes of an HA pair fail. Load-sharing mirrors are not suitable for clusters consisting of a single HA pair.

About this task

If you create an LSM on the same node, and the node is unavailable, you have a single point of failure, and you do not have a second copy to ensure the data remains accessible to clients. But when you create the LSM on a node other than the one containing the root volume, or on a different HA pair, your data is still accessible in the event of an outage.

For example, in a four-node cluster with a root volume on three nodes:

For the root volume on HA 1 node 1, create the LSM on HA 2 node 1 or HA 2 node 2.
For the root volume on HA 1 node 2, create the LSM on HA 2 node 1 or HA 2 node 2.
For the root volume on HA 2 node 1, create the LSM on HA 1 node 1 or HA 1 node 2.

Steps

Create a destination volume for the LSM:

You must replace the variables in angle brackets with the required values before running this command.
```
volume create -vserver <SVM> -volume <volume> -aggregate <aggregate> -type DP -size <size>
```
The destination volume should be the same or greater in size than the root volume.

It is a best practice to name the root and destination volume with suffixes, such as _root and _m1.

For complete command syntax, see the man page.

The following example creates a load-sharing mirror volume for the root volume svm1_root in cluster_src:
```
cluster_src:> volume create -vserver svm1 -volume svm1_m1 -aggregate aggr_1 -size 1gb -state online -type DP
```
Create a replications job schedule.
Create a load-sharing mirror relationship between the SVM root volume and the destination volume for the LSM:

You must replace the variables in angle brackets with the required values before running this command.
```
snapmirror create -source-path <SVM:volume> -destination-path <SVM:volume> -type LS -schedule <schedule>
```
For complete command syntax, see the man page.

The following example creates a load-sharing mirror relationship between the root volume svm1_root and the load-sharing mirror volume svm1_m1:
```
cluster_src::> snapmirror create -source-path svm1:svm1_root -destination-path svm1:svm1_m1 -type LS -schedule hourly
```
The type attribute of the load-sharing mirror changes from DP to LS.
Initialize the load-sharing mirror:

You must replace the variables in angle brackets with the required values before running this command.
```
snapmirror initialize-ls-set -source-path <SVM:volume>
```
Initialization can be time-consuming. You might want to run the baseline transfer in off-peak hours.

For complete command syntax, see the man page.

The following example initializes the load-sharing mirror for the root volume svm1_root:
```
cluster_src::> snapmirror initialize-ls-set -source-path svm1:svm1_root
```

Create and initializing load-sharing mirror relationships

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