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We have a small organization, with two Hyper-V R2 hosts. We're adding a third host, and will need to migrate some VMs from one of the existing hosts onto the new host. The idea is to replace the over-specced server for a small site with 10 users with a smaller server, and then use the big beefy server back at our main site to split the load and improve reliability. Complicated, but the only way I can think of to correct this initial misallocation of resources.

What's the best way to do this, minimizing downtime? I am OK with downtime if needed, but it would be nice not to need much. The VMs are for a small site, but include a domain controller and primary file server, so it will be disruptive. We do not have centralized storage--we have DAS for both the new and old VM hosts. SATA. I think the network at this remote site is gigabit, but it may only be 10/100. I have multiple NICs on both machines, so I could use a crossover Ethernet to speed up the network aspect.

I know that SCVMM can be used to do a "quick migration", that may be only a few minutes on a fast network. It's expensive for an organization our size, especially with only 3 Windows VM hosts. Is there an easy way (or complicated way that I can get step by step directions for) to do this without purchasing this product? If I download the trial (this is really a one-time migration deal so I'm okay with the 120 day limit), will it be easy to continue using the built-in Hyper-V product without locking myself in to upgrading to SCVMM?

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Without shared storage you need to plan on downtime. The downtime is going to depend on the size of your VMs, especially massive VMs stored on regular sata disks can take HOURS, I just migrated a 1.2TB VM over a 1GB connection that was stored on SATA disks migrating to SATA disks. It took about 14 hours in total. I moved a 600GB VM on some enterprise SAS drives over a 1GB connection and that only took about 2 hours. So the disk system plays a HUGE part. Feel free to install the SCVMM trial, it goes in and out cleanly and will work side by side with the built in Hyper-V tools. There are two versions of SCVMM, the enterprise version and the small business version. The SMB version is restricted to managing 5 systems and is considerably cheaper so if you like SCVMM that might work well for you. All in all my best long term recommendation is to start budgeting for some shared storage and do some testing with SCVMM.

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Agreed. You're looking at some significant downtime with no shared storage. You're going to have to copy over those VMs over the net to the other host's storage first. Also, even if they were using shared storage you wouldn't need SCVMM to do this. The built-in HyperV tools allow you to live and/or quick migrate hosts. – Tatas Jul 8 '11 at 16:20
@Tatas--thank you! I did not realize that I didn't need to buy SCVMM to use the live migration. Thanks to your comment, now I see that I can do it using Powerscript. That seems like the way to go to me. Am I correct that using Live Migration, the downtime is minimal regardless of the disk speed (on the order of minutes just to transfer the memory contents, instead of hours?). – Quinten Jul 8 '11 at 21:20
Live migration requires shared storage, which is part of the reason the others have been telling you that your problem would be much easier with it. – Jake Oshins Jul 9 '11 at 16:22
I guess that I am looking for the equivalent of what MS calls "Quick Storage Migration," which is the only option to migrate from one storage solution to another. It appears it is not built-in or available to Powershell, but is a feature only available with SCVMM. I guess we will check out the free 120 day trial and consider purchasing it when it is next feasible. In this case, shared storage would not be helpful at all though, as I am moving a VM from a host in one physical site to a host that is going to move to a second physical site. – Quinten Jul 10 '11 at 22:14
I just finished this process, and I did need to use Quick Storage Migration. Not marking as answered because the answer did not correctly describe the downtime when using SCVMM, which is only 1 minute. It is true that the actual transfer takes a long time, but downtime is minimal. – Quinten Jul 27 '11 at 17:55

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