Skip to main content

Create and initializing load-sharing mirror relationships

Contributors netapp-lenida netapp-aherbin
PDFs

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

  1. Create a destination volume for the LSM:

    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

  2. Create a replications job schedule.

  3. Create a load-sharing mirror relationship between the SVM root volume and the destination volume for the LSM:

    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.

  4. Initialize the load-sharing mirror:

    snapmirror initialize-ls-set -source-path <SVM:volume>

    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