add backup restore doc link

docs/CONFIG-VARS.md

@@ -209,7 +209,7 @@ Custom policy:
 | autoscaling_enabled | Enable cluster autoscaling | bool | true | |
 | ssh_public_key | File name of public ssh key for jump and nfs VM | string | "~/.ssh/id_rsa.pub" | Required with `create_jump_vm=true` or `storage_type=standard` |
 | cluster_api_mode | Public or private IP for the cluster api| string|"public"|Valid Values: "public", "private" |
-| enable_multi_zone | Set to true to deploy EKS Node Pools in multiple availability zones | boolean | false | **WARNING: changing this from true to false after infrastructure creation is destructive** |
+| enable_multi_zone | Set to true to deploy EKS Node Pools in multiple availability zones | boolean | false | **WARNING**: changing this from true to false after infrastructure creation is destructive. If you have an existing Viya deployment in your cluster, following the [SAS Viya Platform Operations backup and restore documentation](https://go.documentation.sas.com/doc/en/itopscdc/v_044/itopsmigwlcm/home.htm) is recommended before changing this. |
 
 ## Node Pools