What Is Load Sharing Mirror Volume In SVM - Netapp Cluster Mode

In this blog we will discuss about load sharing mirror volume in svm netapp cluster mode. Below are the few topics which we are going to cover.

What is load sharing mirror volume in SVM ?

How load sharing mirror works

How to create load sharing mirror volume using command line.

What Is Load Sharing Mirror Volume In SVM?

As its name suggest load sharing mirror volume share the load of a source volume. That simple right but the question arises what type of load it share well the answer is read load. It does not share write load of source volume. Source volume is nothing but the volume which is serving data to the client. 

When ever a read request come for source volume ontap will see if any load sharing mirror volume present in the node or not. If its finds a load sharing volume then ontap will route the request to the load sharing mirror volume. This is not applicable for write request.

How Load Sharing Mirror Volume Works ?

In order to understand how load sharing volume works first lets discuss about the layout of load sharing volume. For one source volume there will be load sharing mirror volume in each node of the cluster. The type load sharing mirror volume must be DP which stands for data protection. Now let suppose there is a volume vol1 which is owned by Node 1. Now a user is trying to access the data using a LIF which is present in Node 2. 

In above scenario, first the read request will come to Node 2 then as the volume is present in node 1 ontap will route the request to node 1 via inter cluster switches. This will create a small amount of latency. Now if the node 2 has load sharing mirror volume then the read request will be served  back from node 2 itself which will lower the latency and network traffic.

How To Create Load Sharing Volume Using Command Line.

There are three steps to create a load sharing mirror volume. We are going to discuss about these one by one. We will assume that we have two nodes in cluster. The source volume name is vol1 which belongs to SVM vs1.

Step 1: Create Load Sharing Mirror Volume In Each Node Of The Cluster

The following command creates a load-sharing mirror volume for the volume vol1 of the SVM vs1 on each node of the cluster. The naming convention of the load-sharing mirror volumes are recommended by netapp.

volume create -vserver vs1 -volume vol1_m1 -aggregate aggr_node1 -size 30MB -type DP

volume create -vserver vs1 -volume vol1_m2 -aggregate aggr_node2 -size 30MB -type DP

Step 2: Create Snapmirror Relation Between Source And Mirror Volume

Before replicating data from the source volume to the load-sharing mirror destination volumes, we need to create a snap mirror relationships for each load sharing mirror volume. In our case we need to create two mirror relationship. The type of snapmirror relationship must be LS which stands for Load Sharing.

snapmirror create -source-path vs1:vol1 -destination-path vs1:vol1_m1 -type LS

snapmirror create -source-path vs1:vol1 -destination-path vs1:vol1_m2 -type LS

Step 3: Start Baseline Copy for Load Sharing Mirror Volume

We need to  initialize the load-sharing mirrors to start a baseline copy between the source volume and the load-sharing mirror destination volumes. Once the copy is finished the destination volume will be ready to server the data. The following command creates a baseline copy of the source volume named vol1 to all of the load-sharing mirrors.

snapmirror initialize-ls-set vs1:vol1

How To Create Load Sharing Mirror Volume In SVM - Video Tutorial

Below is the video which shows how to create load sharing mirror volume in SVM netapp cluster mode in command line.