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andre_froneman1
Contributor
Contributor

Vmotion questions

Hi All

I would like to know what the limitations of Vmotion is in regards to physical ESX servers being on the same network, same location, connected to same SAN, same IP range, same subnet and so forth.

Would anyone be able to provide some clarity?

If these questions have been looked at on another forum please provide the URL.

Thank you in advance.

Regards

Andre

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10 Replies
ascari
Expert
Expert

Hi Andre,

you receive an error when you try to migrate a VM when:

-VM has an active connection to an internal vSwitch

-VM has an active connection to a cd rom o floppy image mounted

-VM has its cpu affinity set to run on one or more specific physical cpus

-VM is in a cluster enviroment (MSCS)

I hope this can help you.

Bye Alberto

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andre_froneman1
Contributor
Contributor

Hi Alberto

This is great, thanks for your feedback.

Regards

Andre

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vams
Contributor
Contributor

Hi Andre,

As alberto mention all this required for vmotion. and one most imp point in this regards is the host on which your are doing/configuring vmotion they should have same type of processor family. Means if one has intel then second should have the same then only we are able to go for the vmotion. For vmotion HA and DRS should be enable in yourr environment.

http://www.vmware.com/products/vi/vc/vmotion_features.html (this link also help you to know more about vmotion)

may this info also helpful to you.

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Brianck
Enthusiast
Enthusiast

Best practice is also putting VMotion should be on it's own network... :smileygrin:

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Texiwill
Leadership
Leadership

Hello,

vMotion traffic can be routed so it does not need to live on its own subnet. But it should be on its own network just for Security reasons as vMotion is a cleartext protocol of the memory image of the VM.

You can vMotion between different processor types and families but you need to tune the vMotion using the specialized code to disable/enable specific CPU abilities. You need to fully understand the processor to do this however. Note, that this will only work for 32 bit VMs. 64Bit VMs must have the same CPU and processor family in order to vMotion. The guest OS has also have support for this. For example, Linux does not like changing processors during vMotion but some versions of Windows can handle it quite well. So its better to match processors IMHO.

You can vMotion VMs on private vSwitches, but you need to modify files on the ESX server to do this.


Best regards,

Edward L. Haletky

VMware Communities User Moderator

====

Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education. CIO Virtualization Blog: http://www.cio.com/blog/index/topic/168354, As well as the Virtualization Wiki at http://www.astroarch.com/wiki/index.php/Virtualization

--
Edward L. Haletky
vExpert XIV: 2009-2023,
VMTN Community Moderator
vSphere Upgrade Saga: https://www.astroarch.com/blogs
GitHub Repo: https://github.com/Texiwill
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Brianck
Enthusiast
Enthusiast

I thought just the command to start VMotion was in clear text but the memory dump itself was not in clear text...

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Texiwill
Leadership
Leadership

Hello,

Currently everything is cleartext. The issue at hand is that vMotion must be FAST so that the VM does not know anything is happening. Encryption takes quite a bit of time to do properly.


Best regards,

Edward L. Haletky

VMware Communities User Moderator

====

Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education. CIO Virtualization Blog: http://www.cio.com/blog/index/topic/168354, As well as the Virtualization Wiki at http://www.astroarch.com/wiki/index.php/Virtualization

--
Edward L. Haletky
vExpert XIV: 2009-2023,
VMTN Community Moderator
vSphere Upgrade Saga: https://www.astroarch.com/blogs
GitHub Repo: https://github.com/Texiwill
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vams
Contributor
Contributor

Hi texiwill,

As you said vmotion is possible in to differrent family processors for the 32 bit OSes only. We are having some infrastructre with 32 bit server and having issue with vmotion can you provide us some technical papers for the configuration of this processor setting in two different families. It will help us to do same.

any link or documents which can help us...

Thanks in advance....

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Vinn
Contributor
Contributor

Texiwill,

Could you clarify this for me? I have been told by VMware Systems Engineers that I need to have a separate NIC in the server for each subnet that my guest OSes are on for VMotion. This sounded a little suspicious to me, so I decided to do a bit of research in case there was a miscommunication. It would seem that your post says the opposite, so I want to clarify my question:

My ESX host will have VMs on 10.133.16.x and 10.133.17.x and 10.133.19.x and 10.133.20.x. We use 24-bit masks, so these are separate subnets. Do I need to have four NICs in my ESX server for VMotion?

Thanks in advance!

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Ken_Cline
Champion
Champion

My ESX host will have VMs on 10.133.16.x and 10.133.17.x and 10.133.19.x and 10.133.20.x. We use 24-bit masks, so these are separate subnets. Do I need to have four NICs in my ESX server for VMotion?

No! Regardless of how many subnets your VMs will communicate on, you need only one pNIC for VMotion (although it is best practice to have two for redundancy) per host.

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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