Upgrade ESX 3.5 to ESXI 4.1?

We have 2 existing ESX hosts running 3.5.  One host is not in use so I can wipe the drives and install ESXi4.1 fresh.  I know ESXi is the future so should we take this oppertunity to go to ESXi or just go from 3.5 to 4.1 ESX?  

The live ESX server running 3.5 is booting from fiber storage if that makes any difference.  

Is ESX 3.5 to ESXi 4.1 possible?  If so how?
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bgoeringConnect With a Mentor Commented:
If you have the time and don't mind the reconfiguration then go ahead with ESX to ESXi now. I would recommend installing to USB rather than local HD or SAN boot.

No upgrade path exists ESX to ESXi - it takes a clean install. Also unless you are running your vCenter on a 64-bit OS there isn't an easy upgrade path there as the 64-bit OS is required for the new vCenter. Be sure you upgrade vCenter first!

Good Luck
Andrew Hancock (VMware vExpert / EE MVE^2)Connect With a Mentor VMware and Virtualization ConsultantCommented:
ESX 4.1 is the last version of ESX, I would opt for a ESXi installation.

Check the VMware HCL (Hardware Compatability Lists) here to see if your server is supported.




There is an upgrade path from ESX 3.5 to ESX 4.1,

do you mean your existing server boots from SAN?
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Here's a link to the upgrade guide


So you need to make a choice,

ESX 3.5 to ESX 4.1?

ESX 3.5 to ESXi 4.1 (new install)?

and do you want to keep boot from SAN or USB?
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jcwiletsAuthor Commented:
Thanks everyone.

There is no vcenter server we are just putting one in so thats a clean 64bit vcenter server.  So to clarify.

Server A - 3.5 ESX ( all VMS and ESX is boot from the DAS, SAN)
Server B - Standby server nothing running on it 3.5 ESX (easy wipe and load ESXi 4.1
Server C - Brand New easy load ESXi 4.1

So maybe the best route is to use USB to a clean 4.1 ESXi.  I can really just use a USB key and change the boot point?
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Yes, I would recommend the use of USB Flash Drives, easy install and backup.
jcwiletsAuthor Commented:
Any USB drive recommendation?

So I change the boot point and boot my USB ESXi 4.1 and I have an all ESXi 4.1 environment.  Which is ideal.  I will probably have to re-import the VM's then migrate them to version 7 machines but that should all be pretty doable.
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
oh yes, does use cheap Walmart ones, HP or SANdisk. (4GB should be fine).

Version 4 VMs will run in an ESX 4.1 environment, you'll just not have access to the newer features.

So upgrade VMware Tools, and then later Upgrade Virtual Hardware.
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Yes, change the Boot Priority to USB, Removal Drive etc
Any quality USB drive should be fine, and 4GB is more than adequate (I think my USB install is on a 2GB key).

Any new servers I have ordered the last year or so I always get with the embedded ESXi which comes on an internal USB or Compact Flash media - no install is even required, just set EFI boot option to boot your ESXi.
jcwiletsAuthor Commented:
Thanks everyone
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