ESX or ESXi? Which to install?

[dlchapman]

We are currently runnning the evaluation version of vSphere with ESXi 4 installed on three hosts. At the start of the new year we will be purchasing the vSphere 4 Advanced Acceleration Kit. We installed ESXi becuase it was touted as the "Next Generation" bare metal hypervisor by VMWare, however I will need ESX installations to take advantage of the 3ware 3DM2 web management utility for our 3ware RAID cards. My question is this: I know I have a choice as to which I care to install but I'm a little confused as to what the significant differences are between ESX and ESXi is. I mean, other than smaller footprint and thus smaller attach surface, is their any real advantage to using ESXi vs ESX?

[dlchapman]

Let me clarify before I get any flame responses. My specific question is why is VMWare touting ESXi as the next-generation bare metal hypervisor when it seems to lack functionality compared to ESX? Does this mean that they'll eventually drop ESX as a product?

[AndreTheGiant]

ESXi will probably be the future.

But vendor must create their agent/utility software also for ESXi... For example Dell and HP have already realize their management software.

Andre

[John Krueger]

If you need the Service Console available with ESX to manage your RAID cards, then install ESX.

Functionally, they are the same. ESX has the Service Console as another management point, but that's available remotely for ESXi via the vCLI.

The hypervisor (VMkernel) is the same in both.

The advantages to going with ESXi:

No knowledge of Linux necessary to operate the Service Console

Less space consumed on disk (the SC consumes, out of the box, around 8GB of disk)

You don't have to worry about security patches for the Service Console (which is based on Red Hat Linux)

Patching ESXi is more akin to updating the firmware on a switch than patching an OS

ESXi is arguably VMware's future direction

The advantages of going with ESX:

The Service Console gives you a full Linux-based management experience of the ESX host

Individual patches can be applied based on the needs of your envionment

The Service Console provides an install location for hardware management or backup agents

ESX was designed to be installed as a hypervisor and management layer, all in one. Then VMware took the hypervisor and bootstrapped it to be run alone on a host as though it were little more than a compute appliance - hardware to deliver resources to run your VMs with the smallest amount of overhead. This became ESXi.

Pick one and run with it based on your needs. Assuming there comes a day when one is no longer available, I would be comfortable saying that your VMs will be migratable to the new platform with little or no pain.

-jk