ESXi 3.5 to 4 Free edition question

what is vmhd?

It should be compatible upward from ESX3 to ESX4 if you know how to migrate them properly. My best bet for your case is use VM converter to migrate the vm's images. If you can join your ESXi host to virtual center, you can use storage Vmotion to move your vm to different storage. Here is the guide:
http://www.virtualizationadmin.com/articles-tutorials/vmware-esx-articles/vmotion-drs-high-availability/storage-vmotion-svmotion-vi-plugin.html

K

Does this work for the free version?
VMHD is virtual machine hard drive

There is no incompatibility. You don't need to 'migrate' per sè...you can simply copy the VM files (vmdk, vmx, etc.) to the new storage location (if there will be a new storage location) since datastore FS is the same (VMFS3). The only tasks you will need to perform is 1. Upgrade VM Tools (do this FIRST), 2. Upgrade the VM Hardware.

Regards,
~coolsport00

....Does anyone know if ESXv3....

I thought you have ESX3 (paid version) comes with virtual center. If you don't have virtual center, you can try to run svmotion from command:
http://www.vmware.com/pdf/vi3_35/esx_3/r35u2/vi3_35_25_u2_rcli.pdf

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K

My thought was to remove the virtual harddrives then move them to my NAS.  Then replace the current drives with largers ones.  Then install ESXi4.1.  Move the files over.  mount them.done

I may be confused a bit here by your terminology. When you say you're going to replace hard drives...do you mean in your ESXi HOST? If so, those are actually physical drives. When you say 'virtual hard drives', I'm thinking the VMDK files...or virtual disks...of the VMs. Can you please clarify what it is you're performing? Do you have a 2nd server/host you're installing ESXi 4/4.1 on? Are you still going to have ESX 3.x? What specific legacy 3 ESX 'edition' are you running?...ESX or ESXi? 3.0 or 3.5? I guess the version number doesn't really matter too much...VM data is all kept on VMFS3 file system as it is in version 4.

If you are rebuilding your current host and solely just need to get your VMs off, you can use a free tool to simply copy or move your VM folders off your current datastore. You can use Veeam FastSCP (http://www.veeam.com/vmware-esxi-fastscp.html). Install it on your local workstation, connect to your ESX or ESXi host, then move the VMs to a storage drive connected to your workstation...either external drive or mapped drive, as long as there's enough space to hold all your VMs. Once you're done rebuilding your host, you can move the VMs back to your host, re-add them to Inventory (right-click on the .vmx file within each VM folder), then upgrade the Tools then Hardware as I mentioned above.

Hope that helps. Please clarify if I'm not understanding you.

Regards,
~coolsport00

Yes,

I am going to be replacing a few drives in my hostserver.  Therefore I am moving my VMDK files off to our NAS as a temporary storage until I get the ESXi 4 installed.  Right now the drives are at capacity and the hostserver is running v 3.1 of ESXi.  Also I cannot move the VMs while they are turned on correct?  Would you recommend using the FastSCP or the VMware converter tool?  

Ah...ok :)

Hmm...well, you're limited to what you can do really with ESXi, regardless of the version, unless of course you have the paid version, which you mentioned you are not using. So, that being said, if you use vCenter Converter Standalone, you can convert/move your VMs using that UNLESS the NAS storage is connected somehow to your ESXi host. Now, with FastSCP, your VMs do need to be powered down to move or copy them off your datastore, but the nice thing about FastSCP is you don't need only ESX/i datastore storage....FastSCP 'sees' local storage on the workstation it's installed on; so it sees an external drive, or any mapped drive (and of course local storage too) as storage under the 'Servers -> My Computer' heading. So, if you are able to see datastore/NAS storage using Converter that has enough free space to place your VMs, use the Converter. If not, but you do have free space on your NAS, use FastSCP. I personally would use FastSCP...it tends to go a bit faster than converter. The choice is really up to you.

Regards,
~coolsport00