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Hardware Thread, Virtualising our network. How would you do it? in Technical; How would you do it? I am in the planning stage for implementing a virtual network. We currently have 6/7 ...
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    Virtualising our network. How would you do it?

    How would you do it? I am in the planning stage for implementing a virtual network. We currently have 6/7 servers. They are mainly server 2003 so I would be looking to upgrade to server 2008 R2.

    1 x admin (which runs our MIS)
    3 x curriculum (User accounts and file storage)
    1 x VLE Server (Moodle)
    1 x test server
    1 x Exchange 2010 (Soon to be, just installing and setting up now)

    We have around 400 desktops and 80 laptops.

    From reading these forums a decent setup would be one physical DC and 2 virtual servers (clustered & both DCís) and a SAN. This would allow for a failure on any of the servers and the network would carry on running using either VMware or Hyper-V. VMware is looking like my preferred solution but this is purely personal preference.

    QUESTIONS

    1. Did any of you have to upgrade your switches / network backbone prior to virtualizing. Our switches are probably at least 5 years old and having a current issue with switches crashing when running large backups across the network using backup exec with a backup server at the opposite end of the school.

    1a. What speed switches, type of cabling, bandwidth do you use on your virtual network?

    2. Would you go for one physical DC and 2 virtual servers (both DCís) and a SAN? Or would you approach it differently?

    3. How long do you keep your desktops? We currently refresh most after 3 years but I was thinking we could probably get 5-6 years out of them virtualized as the demand on the actual desktop is less.

    4. How do you know what spec servers to get for a virtual setup?

    I know enough about virtualisation but want peoples opinions and experience of setting it up and helping to draw together a plan.

    Thanks

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    Physical DC is handy but not essential, are any of your old servers still in warranty \ worth keeping? Could re-use one of those.

    We've got HP managed ProCurve switches all over, still 100Mb to desktop with 1Gb fiber link back per switch (usually 24 ports). We have our VMWare set up to use tagged VLANs so we can define network membership at the VM level (admin or teaching on separate networks)

    If you can stretch to a 3rd host it's better for redundancy as if one should go down you're not running at 100% utilisation on the existing host. Comes down to money though.

    Desktops we used to have on a 3yr cycle but the last lot went to 5 years and since Core2Duo came out performance is still good. Our Stone kit has 5yr warranty so makes sense to align the replacement cycle to that.

    Haven't virtualised desktops yet as the numbers don't add up financially and you'll most likely need additional servers for VDI on top of the ones you purchase to run your servers, unless you go for something like Kaviza that uses DAS you'll also need more disks on your SAN as VDI hammers it.

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    Single point of failure there would be the san. Consider a standalone server that could mirror services and host machines in case of failure. implement DFS on your file shares, host one file server on the cluster, one of the standalone, same with DC's, and backup the cluster to the standalone so you can start the vm's albeit with a little less ram and processor.

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    Are you moving away from RM CC4?

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    We are thinking about it, but weighing up all the options first. We would only move if there was a fear benefit to students and staff.

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    QUESTIONS

    1. Did any of you have to upgrade your switches / network backbone prior to virtualizing. Our switches are probably at least 5 years old and having a current issue with switches crashing when running large backups across the network using backup exec with a backup server at the opposite end of the school.

    1a. What speed switches, type of cabling, bandwidth do you use on your virtual network?

    We kept the existing network in place (HP Procurve - quite old) for clients, but implemented an iSCSI network at gigabit speed between SAN and VMWare servers, and enabled jumbo frames on the iSCSI LAN. The VMWare servers needs lots of NICs - more than one connection (for redundancy) on every connected network. Ours have 10 NICs each, all running at gigabit.

    2. Would you go for one physical DC and 2 virtual servers (both DC’s) and a SAN? Or would you approach it differently?

    We have two domains with two DCs on each, and have virtualised everything. If we completely lost our DCs, well, we'd be in a big mess, but in terms of DCs, you could even restore the vmdk images of the DCs and temporarily run them on a standalone exsi server (if vmware), god forbid. We implemented the SAN first, connected to physicals, and virtualised subsequently. I beleive that you'll need the SAN if you want centralised storage and a high level of fault tolerance - all of your servers can see the SAN, so if one physical dies, anothers can take over, and moving virtualised hosts between physical servers is easy (like VMWare's VMotion).

    3. How long do you keep your desktops? We currently refresh most after 3 years but I was thinking we could probably get 5-6 years out of them virtualized as the demand on the actual desktop is less.

    We have a lot of obselete kit, and I can't say demand on the desktop has changed really in our case. I'd say we virtualised more for the cost, power and fault tolerance rather than performance to be honest.

    4. How do you know what spec servers to get for a virtual setup?

    There is software out there to find out loading on servers from clients and to do analysis in terms of what you need. We were offered software and consultancy, but the costs were so prohibative. We would not have been able to afford the virtualisation if we'd have scoped the project carefully, so it was more wet finger in the air, and so far it has worked for us.

    Hope that this helps.

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    If you have 6/7 servers, then why not use some of them as your hosts to, they cannot all be end of life, if your installing Exchange 2010 on one they can't be to bad. They could be the "failover" boxes.

    From experience, a seperate DC is necessary, whether it is one stored on the local drive on a server, or a different physical box, you need 1 DC to come online before a failover cluster (in a HyperV environment)will come online.

    As for your switches, I am assuming you mean connecting your SAN and servers. You can use any "decent" switch but think about 10GBe SANs etc depending on your budget.

    If you are buying new servers, then work out how many cores you are using already, work out how much RAM you are using. Then you need to have more then that, remember for Virtual Cores, a thread is a core so a Quad Core with 8 threads is 8 Virtual Processors, so you can get 16 Virtual Cores from a 8 core Intel Server etc. If you are only buying two servers and expect failover then each of those 2 servers much be able to run alll your needed services, otherwise you have no failover at all. This is why I suggested using your old servers as hosts to.

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    I went with VMware and used two old Dell Poweredge 2950 with 16Gb RAM in each but with a brand new DLink 6150 SAN with a 1 and 5 array and new Dlink Switches. I have a 10GbE fibre backbone and run 2x1Gb trunked fibre links to each on my remote switches.
    Storage is run in a separate VLAN and the Dells are split on either side of the site, one with the NAS and the other with the SAN as part of my DR. Next step will be a second controller for the SAN and upgrade to the full licence so I can migrate my VMs in case of disaster. I have a venerable Dell 830 as a backup DC but all my production servers are VMs on W2k8R2 - I also moved to W7 desktops after the joys of 'compatible' server w2k3 got too much for me!

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