Microsoft Multi-Site Failover Cluster for DR & Business Continuity


Not every organisation looses millions of dollar per second but some does. An organisation may not loose millions of dollar per second but consider customer service and reputation are number one priority. These type of business wants their workflow to be seamless and downtime free. This article is for them who consider business continuity equals money well spent. Here is how it is done:

Multi-Site Failover Cluster

Microsoft Multi-Site Failover Cluster is a group of Clustered Nodes distribution through multiple sites in a region or separate region connected with low latency network and storage. As per the diagram illustrated below, Data Center A Cluster Nodes are connected to a local SAN Storage, while replicated to a SAN Storage on the Data Center B. Replication is taken care by a identical software defined storage on each site.  Software defined storage will replicate volumes or Logical Unit Number (LUN) from primary site in this example Data Center A to Disaster Recovery Site B. Microsoft Failover cluster is configured with pass-through storage i.e. volumes and these volumes are replication to DR site. In the Primary and DR sites, physical network is configured using Cisco Nexus 7000. Data network and virtual machine network are logically segregated in Microsoft System Center VMM and physical switch using virtual local area network or VLAN.  A separate Storage Area Network (SAN) is created in each site with low latency storage. Volumes of pass-through storage are replicated to DR site using identical size of volumes.

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                                     Figure: Highly Available Multi-site Cluster

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                           Figure: Software Defined Storage in Each Site

 Design Components of Storage:

  • SAN to SAN replication must be configured correctly
  • Initial must be complete before Failover Cluster is configured
  • MPIO software must be installed on the cluster Nodes (N1, N2…N6)
  • Physical and logical multipathing must be configured
  • If Storage is presented directly to virtual machines or cluster nodes then NPIV must configured on the Fabric Zones.
  • All Storage and Fabric Firmware must up to date with manufacturer latest software
  • An identical software defined storage must be used on the both sites 
  • If a third party software is used to replicate storage between sites then storage vendor must be consulted before the replication. 

Further Reading:

Understanding Software Defined Storage (SDS)

How to configure SAN replication between IBM Storwize V3700 systems

Install and Configure IBM V3700, Brocade 300B Fabric and ESXi Host Step by Step

Application Scale-out File Systems

Design Components of Network:

  • Isolate management, virtual and data network using VLAN
  • Use a reliable IPVPN or Fibre optic provider for the replication over the network
  • Eliminate all single point of failure from all network components
  • Consider stretched VLAN for multiple sites 

Further Reading:

Understanding Network Virtualization in SCVMM 2012 R2

Understanding VLAN, Trunk, NIC Teaming, Virtual Switch Configuration in Hyper-v Server 2012 R2

Design failover Cluster Quorum

  • Use Node & File Share Witness (FSW) Quorum for even number of Cluster Nodes
  • Connect File Share Witness on to the third Site
  • Do not host File Share Witness on a virtual machine on same site
  • Alternatively use Dynamic Quorum

Further Reading:

Understanding Dynamic Quorum in a Microsoft Failover Cluster

Design of Compute

  • Use reputed vendor to supply compute hardware compatible with Microsoft Hyper-v
  • Make sure all latest firmware updates are applied to Hyper-v host
  • Make manufacture provide you with latest HBA software to be installed on Hyper-v host

Further Reading:

Windows Server 2012: Failover Clustering Deep Dive Part II

Implementing a Multi-Site Failover Cluster

Step1: Prepare Network, Storage and Compute

Understanding Network Virtualization in SCVMM 2012 R2

Understanding VLAN, Trunk, NIC Teaming, Virtual Switch Configuration in Hyper-v Server 2012 R2

Install and Configure IBM V3700, Brocade 300B Fabric and ESXi Host Step by Step

Step2: Configure Failover Cluster on Each Site

Windows Server 2012: Failover Clustering Deep Dive Part II

Understanding Dynamic Quorum in a Microsoft Failover Cluster

Multi-Site Clustering & Disaster Recovery

Step3: Replicate Volumes

How to configure SAN replication between IBM Storwize V3700 systems

How to create a Microsoft Multi-Site cluster with IBM Storwize replication

Use Cases:

Use case can be determined by current workloads and future workloads plus business continuity. Deploy Veeam One to determine current workloads on your infrastructure and propose a future workload plus business continuity.  Here is a list of use cases of multi-site cluster.

  • Scale-Out File Server for application data-  To store server application data, such as Hyper-V virtual machine files, on file shares, and obtain a similar level of reliability, availability, manageability, and high performance that you would expect from a storage area network. All file shares are simultaneously online on all nodes. File shares associated with this type of clustered file server are called scale-out file shares. This is sometimes referred to as active-active.

  • File Server for general use – This type of clustered file server, and therefore all the shares associated with the clustered file server, is online on one node at a time. This is sometimes referred to as active-passive or dual-active. File shares associated with this type of clustered file server are called clustered file shares.

  • Business Continuity Plan

  • Disaster Recovery Plan

  • DFS Replication Namespace for Unstructured Data i.e. user profile, home drive, Citrix profile

  • Highly Available File Server Replication 

About Raihan Al-Beruni

My Name is Raihan Al-Beruni. I am working as an Infrastructure Architect in Data Center Technologies in Perth, Western Australia. I have been working on Microsoft technologies for more than 15 years. Other than Microsoft technologies I also work on Citrix validated solution and VMware data center virtualization technologies. I have a Masters degree in E-Commerce. I am certified in Microsoft, VMware, ITIL and EMC. My core focus is on cloud technologies. In my blog I share my knowledge and experience to enrich information technology community as a whole. I hope my contribution through this blog will help someone who wants more information on data center technologies.
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4 Responses to Microsoft Multi-Site Failover Cluster for DR & Business Continuity

  1. Alex says:

    I would like to know once the Multi site cluster is configured, If the primary site itself is down, Will the DR site will start automatic or manual intervention required.

    Like

    • It will be automatic if you have configured all properties correctly. If you misconfigured anything and WAN topology has any issue you will run into trouble. So plan everything before you configure multi-site cluster.

      Like

      • Alex George says:

        Hi Raihan
        Thanks for the response, I would like to know more about the storage front, what all prerequisite need to be there and also i would like to know if primary site is down how the storage comes up automatically .

        Like

      • East site will have separate storage area network or shared storage. You need to search SAN in my blog or google. Storage should come automatically if you configured correctly

        Like

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