To Cluster or Not to Cluster?  That is the Question.

Posted on 2014-07-17
Last Modified: 2014-07-22
Some background...I just received two new servers and a SAN.  The servers are running VMware and are setup as two nodes in a clustered environment.  While I got some crash-course training for VMware, I am a fresh fish to this game.  I am setting up a new domain infustructure using all VMs running Windows Server 2012.  We are a small shop that operates from 8-5 so if there is some down time for maintenance after hours or the weekend it is not a big deal.  

I am in the process of getting setting up a Server 2012 File Server, and Exchange 2013 Server and a SQL 2014 Server.  In your opinion, would you you create clusters for the File Server, Exchange Server and SQL Server?  To do so, I would need to purchase an additional license for SQL and Exchange.  

If my logic is correct, the clustered environment of these servers would protect me against an software OS failure.  I already have vSphere HA so if one of my ESXi hosts goes down then the VMs would be transfered to another ESXi host.  Therefore, the Windows clusters don't provide me any advantage if a hardware failure takes place.  

So once again, would you run these Windows Servers in a cluster or just as a single VM?

I appreciate all your feeback!
Question by:csimmons1324
    LVL 19

    Accepted Solution

    Thats depends what kind of failures what want to be protected:

    You can virtualize and create a "cluster" with both servers running Windows 2012, you will get protected against hardware failures but if one service fail, this configuration causes a outage. Server running virtual machines fails, all machines will be moved to the other. You can use vmware or hyper-v, is quite similar.
    Or can create an old style cluster, clustering your SQL, Exchange and file services and get redundancy if server or service fail, but you need twice licences of all, and some of them more expensive (Exchange requires enterprise).
    LVL 4

    Assisted Solution

    by:Philip Portnoy

    please note that cluster does not only provide High availability. It also makes day-to-day maintenance easier.
    For SQL Server - if you're financially capable to purchasie 2 Enterprise editions than I'd recommend you to build Always On HA cluster  - again, you'll get easier maintenance, you'd be able to run backups and reporing on secondary server.
    If you have Standard edition - then 1 SQL Server with vMotion for HA will be enough.

    For file server having a cluster if you're using just 1 SAN is the best way to go, though if you have multiple SANs/sites I'd recommend using DFS replication.

    For Exchange there's no such thing as a cluster (in a way we're used to treat it). But I'd recommend setting up Database Availability Group - again, you get easier maintenance and a chance to balance the load a bit.
    LVL 4

    Expert Comment

    by:Philip Portnoy
    Statement used previously by Miguel Angel Perez Muñoz is false - Exchange does NOT need Enterprise for HA.
    LVL 1

    Assisted Solution

    by:Mayson Arnagiri
    Documentation below can assist with this,

    My personal view - if you have HA, and so few servers to implement, create the VM's on the hosts and load balance between the 2. As long as HA and your network interfaces are configured correctly there can be much resilience and a cost effective implementation.
    You need to also ensure that your network layer is configured correctly. The hosts and the SAN configured with gig fiber channels, and these connect back to the network layer how? this must have fail-over structure in place (in case of network issues)

    Good luck...

    Author Comment


    I do only have one SAN.  As for use the DAG do I am assuming that I need multiple Exchange servers, correct?
    LVL 4

    Expert Comment

    by:Philip Portnoy
    Yes, you will need 2 Exchange servers (and 2 Exchange licenses, though Standard is enough if you're not planning on having >10 databases or some other complex stuff).
    You can balance only databases, or you can make second server a CAS as well. In this case you will need NLB (which might be just any Windows system or special hardware if you have it) to balance user HTTPs requests between servers.

    Author Comment


    I am new to a A LOT of this stuff (VMware, Windows Clusters, Network Layers, etc.).  All of the VMware / HA stuff was setup by a consultant onsite while he gave me some basic training on VMware.  The SAN and ESXi hosts are configured using iSCSI connections using two NICs in each host running through a gigabit switch.
    LVL 68

    Assisted Solution

    You can cluster SQL standard in a 2-note active-passive setup and that would require only a single SQL license.  I suspect that's true for Exchange as well, since only one node is ever active at any given time, but I can't say that for sure.

    Write Comment

    Please enter a first name

    Please enter a last name

    We will never share this with anyone.

    Featured Post

    Free Trending Threat Insights Every Day

    Enhance your security with threat intelligence from the web. Get trending threat insights on hackers, exploits, and suspicious IP addresses delivered to your inbox with our free Cyber Daily.

    Email statistics and Mailbox database quotas You might have an interest in attaining information such as mailbox details, mailbox statistics and mailbox database details from Exchange server. At that point, knowing how to retrieve this information …
    Check out this infographic on what you need to make a good email signature that will work perfectly for your organization.
    Via a live example, show how to set up a backup for SQL Server using a Maintenance Plan and how to schedule the job into SQL Server Agent.
    Viewers will learn how to use the SELECT statement in SQL to return specific rows and columns, with various degrees of sorting and limits in place.

    779 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    17 Experts available now in Live!

    Get 1:1 Help Now