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Ive been trying to search for an answer to this but i cannot find the answer im looking for.

Im setting up a new exchange server 2013 DAG solution on a DELL VRTX with 3 nodes of ESXI 5.5 which includes shared storage in the chassis.

There are about 600 users that will be loaded on exchange. I've setup 2 virtual machines of server 2012 of 200GB each and about to install Exchange 2013 to make them DAG servers. But before i do that - i wanted to get my storage right. I have a 4TB datastore (which all hosts can successfully see) which i want to store all exchange mailboxes and data.

I dont quite understand how to go about this... Do i mount the datastore on the host where the first virtual windows server 2012 is on? But then i wont be able to mount it on the second virtual server 2012 at the same time.

Do both servers have to have access to the exact same datastore? or should it be 2 separate datastores mounted on both windows 2012 servers which will replicate to each other? If that is the case then i will have to split the 4TB?

Also, do i need to install Hyper-V if im already virtualizing the servers?

Please can you clear these things out for me? and forgive me for my ignorance!

Beast14
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  • Not to bum you out or anything, but the main purpose of using DAG's are high-availability as you might already now. What happens if your shared storage goes down? The most common implementation these days of Exchange are standalone servers with RAID6 or even JBOD disks, just to rule out any kind of hardware failure across the DAG. – pauska Nov 06 '14 at 15:43
  • DAG's don't and can't use shared storage between the mailbox servers. Each database disk is individual to the server. – mfinni Nov 06 '14 at 17:03
  • @pauska - Yes i am aware of that. Unfortunately the company i am doing this for has received wrong information from my employer so i cannot do anything about it but make the best of the hardware they bought. I am also aware that if the chassis or network switch fails they will be royally screwed as all 3 blades are in one chassis. – Beast14 Nov 06 '14 at 17:49
  • @mfinni thank you - i understand now. So i can safely assume that both individual disks will replicate to each other? and does that mean i have to split the 4TB? – Beast14 Nov 06 '14 at 17:51
  • The disks don't replicate at the storage layer - the databases replicate using DAG technology. Please go read up on this before implementing; possibly consider hiring a contractor with an explicit skills-transfer clause so that he or she can get you up to speed. – mfinni Nov 06 '14 at 17:52
  • @mfinni Yes sorry i meant to say replicate using DAG, not through the storage layer. thank you! – Beast14 Nov 06 '14 at 18:00

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The keyword is shared storage. That means that it's shared between the 3 vSphere hosts. That means that they all connect to and provision from that shared storage. You should connect 1 host to the storage, create a datastore, then connect your other hosts. They should all see and mount the same datastore.

Once you've done that then you'll provision virtual disks for your virtual Exchange servers from that datastore.

No, the Exchange servers do not need the Hyper-V role installed. Why would they?

Also, I don't know anything about the Dell VRTX, but if you say it presents shared storage to the hosts then it's shared storage, just as if it were presented via iSCSI, FC or FCoE. It's shared, so all 3 hosts access it simultaneously.

joeqwerty
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  • I appreciate your answer! Although all 3 hosts can see the 4TB datastore, not all Virtual Servers such as the 2 i mentioned can mount it as a 4TB virtual hard disk simultaneously (unless im missing something). What i decided to do is leave the 4TB datastore as is, and off that - create individual VHD's for however many mailbox databases i would plan to have each on the first DAG and create the same VHD's on the second DAG. Thereby making it work simply, although its missing the point of 'high availability' - there is no other option i can choose with the available hardware. – Beast14 Nov 06 '14 at 22:41
  • You're kind of understanding it wrong as far as the datastore is concerned. Your virtual machines don't access the datastore directly. Your vSphere hosts access the datastore directly and then you provision virtual storage (VMDK's) from that datastore for your virtual machines. When you create a virtual machine and you create a virtual disk for that virtual machine, that virtual disk is provisioned from the datastore. Also, a virtual disk in vSphere is a VMDK, not a VHD. A VHD is a virtual disk created in Microsoft Hyper-V. – joeqwerty Nov 06 '14 at 22:52
  • Also, in reference to your comment about DAG replication: The DAG replicates the Exchange database at the file/database level. It does not replicate at the disk level. There is no disk replication/synchronization. – joeqwerty Nov 06 '14 at 22:54