Omatsei
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HA & DRS Cluster

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We've got 4 ESX 3.0.1 boxes, 2 of them with Intel CPU's and 2 with AMD. We're looking at building a (or a couple) clusters out of them with both HA & DRS. I know VMotion will freak out if I try to migrate a VM from an Intel box to an AMD box, but I don't know what would happen if DRS tried to do that. Would it continue, despite the warning, or would it stop? If it would stop, would it be a bad idea to have one cluster with both HA & DRS enabled, with all 4 hosts joined to it? Or would it be better to have 2 separate clusters, one for Intel-based hosts, and one for AMD-based hosts? Or, and I don't even know if this is possible, could I build an HA cluster with all 4 hosts, but have 2 DRS clusters inside that, one for Intel, and the other for AMD?

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dmorgan
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I can guarantee you that it would not forcibly VMotion from an Intel box to an AMD box. In fact, I don't even know if it would allow you to add these differing platforms into the same cluster, or at least not without complaining. I know for a fact that it won't vmotion between two different Intel boxes with CPU's that have differing instruction sets, so DEFINITELY not between AMD and Intel. Think about it, it has to move memory state and contents of CPU registers and the like from one system to the other. If those instruction sets differ, then it cannot do that.

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opbz
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- DRS would not be able to do it...it relies heavilly on Vmotion since that will not work neither will DRS. If you want ot set up cluster for drs you will need to setup 2 of them one with the amd other with the intel.

- HA migrates and starts VMs in case of a system failure... It will most likelly be able to start VMs that where running on intel on amd but its not really recommended. I know a lot of VMs will have issues if after every other restart they had different processors

Sounds like what you want to di is to setup 3 clusters 2 for your DRS with 2 servers each and then a third one with the 4 servers. This can not be done. When you create a cluster you have the option of HA or DRS you then drag the servers to the cluster. You can not have a server that is in 2 clusters...

Basically recommend 2 clusters each with DRS and HA enabled one for your intel other for your amd.

opbz
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dmorgan
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I agree. I am not totally sure what would happen if you powered off a VM that was running on an intel platform and powered it on an AMD platform. It may work, or it may complain. You may have Windows licensing issues as well, even if it did work, my guess is if the hardware was differernt enough Windows may ask for you to re-license it. As suggested, I would implement two seperate clusters, two AMD ESX servers in one, and two Intel in the other. This way you can vmotion between the two servers in each cluster, but you will need to divide your VM's accordingly.

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khughes
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I know that is has been done with Intel and AMD in the same cluster. vMotion obviously didn't work between them but you are able to move from platform to platform with a cold migration. I don't know their exact setup because this was when I was first getting into VMware with my company and we were taking a tour of a company that had moved virtual. In my mind HA is no more than a cold migration from a offline ESX host to a running ESX host, so I would test it but it should work. DRS/vMotion are kinda out of the question from platform to platform as you know.

-- Kyle "RParker wrote: I guess I was wrong, everything CAN be virtualized "
Omatsei
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I know HA would work, and I've tested cold migration with both Linux and Windows VM's from Intel to AMD, and vice versa, and that works fine. I'm wondering what would happen if I put all 4 ESX boxes in a HA/DRS cluster? If DRS noticed the AMD boxes getting low on resources, would it forcefully vmotion one of the VM's to an Intel box, or would it notice the incompatibility and stop?

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dmorgan
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I can guarantee you that it would not forcibly VMotion from an Intel box to an AMD box. In fact, I don't even know if it would allow you to add these differing platforms into the same cluster, or at least not without complaining. I know for a fact that it won't vmotion between two different Intel boxes with CPU's that have differing instruction sets, so DEFINITELY not between AMD and Intel. Think about it, it has to move memory state and contents of CPU registers and the like from one system to the other. If those instruction sets differ, then it cannot do that.

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AlexCon
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When you say cold migrate, do you mean shut down the VM on the intel platform, copy the files (disk and config) to the stores that the AMD machines use, add the machine to the cluster and boot it?

Although this may work, the chipsets are still different. AMD and Intel do very much the same thing, but the way they do it is NOT the same. This may cause instability in the long run, and if it's a production machine, I wouldn't want to bet on it. I would just use VMWare converter on the machine and move it from intel to AMD.

Cheers.

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Ken_Cline
Champion
Champion

Cold migration from Intel to AMD to Intel actually works quite well for Windows VMs. It also works well for most Linux VMs -- unless you've optimized the kernel for one architecture or the other (going from Intel to AMD is normally fairly safe...moving an AMD optimized VM to an Intel host can give you heartburn.

Ken Cline

Technical Director, Virtualization

Wells Landers

VMware Communities User Moderator

Ken Cline VMware vExpert 2009 VMware Communities User Moderator Blogging at: http://KensVirtualReality.wordpress.com/
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khughes
Virtuoso
Virtuoso

I have never heard of machines becoming unstable from doing cold migrations between AMD and Intel processors. I've heard of many configurations of AMD and Intel hosts with no problems moving back and forth between them (cold of course)

-- Kyle "RParker wrote: I guess I was wrong, everything CAN be virtualized "
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