RDM and VMFS with ESX 3.5 for CCR Cluster Exchange 2007 on Windows 2008

Posted on 2009-04-29
Last Modified: 2012-08-14
We will use CCR CMS with Windows 2008 ent. failover cluster for Exchange 2007 SP1.  I read a lot of books and documentation.  But it's not clear to me whether it's better to keep using  the VMFS disk for the guest OS and Exchange or using Raw Device Mapping.  Raw Device Mapping datastores will be used for all Exchange storage and databases (mailbox, public folders)

To make myslef clear, here is what I think is best practice, but feel free to correct me:

on the C: drive (VMFS) WIndows 2008 is installed
on the D: drive (RDM) Exchange is installed
on the E: drive (RDM) Transactional Logs
on the F: drive (RDM) Exchange databases

Thank you
Question by:quadrumane
    LVL 8

    Accepted Solution

    Although RDM in theory may give better performance If you can get the performance you require from a VMFS I'd suggest using VMFS for simplicity of backup and DR.
    As far as clustering just wait for ESX version 4, FT will solve your clustering, unless you want the clustered partner to be in a separate physical location.
    Version 4 will be released in 3 weeks.

    Author Comment

    The Failover Cluster must interract with the SAN, not see the disks as if it was  local disks.  So why suggesting VMFS ?  The cluster is local, but later SCR will be used to add another point of failure.  

    Unfortunately I have a deadline.  But in what FT can solve my clustering ?  What is FT ?

    LVL 6

    Expert Comment

    The new Fault Tolerance in the new VMware vSphere product.  protect a server and have another virutal server running in complete lockstep for zero downtime, zero data loss availability.  Check out my blog post the videos should explain it

    Trying to understand your problem here,  you have a SAN,  you want to use Microsoft Windows 2008 Enterprise failover clustering for protection.  Are you using two Windows 2008 Enteprise virtual machines to connect into the SAN for the failover cluster?

    Author Comment

    Thanks for the article on your blog.  I do use 2vCPU for Exchange but I could use one (according to the tests at the Delltechcenter Exchange 2007 is faster with 1 vCPU for 500 heavy mailboxes)

    This new feature will simplify  HA management.  No more Windows cluster.

    I have 3 SAN, I want to use Microsoft Windows 2008 Enteprise failover clustering for Exchange 2007 (CCR)

    On 2 SAN I have 2 LUN of 1TB each available for RDM.  But I don't know if it's better to use RDM disks for the Guest OS too.   I'm not sure about Vmotion when all RDM disks are used for a VM.

    But the Windows failover cluster has to be SAN aware, so this is why I have to use RDM.  

    LVL 19

    Expert Comment

    by:vmwarun - Arun
    What mode are you trying to use for RDM ? Physical Compatibilty Mode or Virtual Compatibility Mode ?

    The benefits of choosing VC Mode is you will be able to use the snapshots feature while the PC Mode does not allow you this.

    Please keep this in mind while using RDM.
    LVL 6

    Assisted Solution

    Just following up on arunraju's point

    You can use Physical Compatibility mode for your RDM's if your wanting to use native SAN tools to snapshot LUNs, etc.  However using physcial compatibility mode means you can't use the VMware snapshot capability.  Your decision depends on whether you want to use your native SAN management / backup tools.

    With regard to your main issue,  you'll have to do some research on the RDM with Vmotion question.  I had a quick look and RDM's and Vmotion doesn't appear to be to much of an issue and is generally supported.  However Vmotion, RDM's and clusters is where it get's tricky and is where you may possibly find it is not supported.

    Get across to the Vmware communities site and raise it as a question,  there are so many Experts over there who will have been through this exact same thing before.  You'll wither find something that'll point you in the right direction or someone will tell you exactly where you stand and what you can and cannot do.

    Good Luck


    Write Comment

    Please enter a first name

    Please enter a last name

    We will never share this with anyone.

    Featured Post

    The problems with reply email signatures

    Do you wish that you could place an email signature under a reply? Well, unfortunately, you can't. That great Exchange/Office 365 signature you've created will just appear at the bottom of an email chain. What a pain! Is there really no way to solve this? Well, there might be...

    Get an idea of what you should include in an email disclaimer with these Top 5 email disclaimer tips.
    Resolve Outlook connectivity issues after moving mailbox to new Exchange 2016 server
    To efficiently enable the rotation of USB drives for backups, storage pools need to be created. This way no matter which USB drive is installed, the backups will successfully write without any administrative intervention. Multiple USB devices need t…
    This tutorial will show how to configure a single USB drive with a separate folder for each day of the week. This will allow each of the backups to be kept separate preventing the previous day’s backup from being overwritten. The USB drive must be s…

    760 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

    8 Experts available now in Live!

    Get 1:1 Help Now