It’s been quite a while since I’ve done a purely technical post.
The original Mac Pro is a 64-bit workstation-class computer that was designed with the unfortunate limitation of a 32-bit EFI. The two models this post discusses are the original 2006 Mac Pro 1,1 and the 2007 Mac Pro 2,1 revision. Both systems are architecturally similar, but the 2006 model features two dual-core CPUs, while the 2007 model has two quad-core CPUs, both based on the server versions of Intel Core 2 chips. I have the 2007 version, which has two Intel Xeon X5365 CPUs for a total of eight cores.
Apple stopped releasing OS X updates for this computer in 2011, with 10.7 Lion being the final supported version. There are workarounds to get newer versions of OS X to run, and a similar concept is being used to make newer versions of ESXi to run. On a side note, getting the newer versions of OS X to run on these old Mac Pros works pretty well, as long as you have the necessary hardware upgrades, which includes a newer video card and potentially newer wi-fi/bluetooth cards.
Like older versions of OS X, older versions of ESXi booted and installed without issue on the old Mac Pros. But at some point, ESXi stopped being supported on these model Macs, due to newer systems using EFI64, and older systems being stuck at EFI32. However, even though it is nearly 10 years old, the 2007 Mac Pro did have eight Xeon CPU cores (and the two quad-core CPUs combined have the same computational power as a single Sandy Bridge-era Core i7 CPU), and is capable of housing 32 GB of RAM, plus four hard drives (six if you don’t care about the drives being seated properly), and has four full-length PCI-e slots and two built-in Gigabit Ethernet ports.
This computer is more than worthy for lab use, and could definitely serve other functions (such as a home media server or NAS). Additionally, when running ESXi, you do not need to have a video card installed, which frees up an extra PCI-e slot.
To get ESXi 6.0 (I used Update 2) to run on the old Mac Pro, you need the 32-bit booter files from an older version of ESXi. The process involves creating an installation of ESXi 6.0 and then replacing the files files included in the link on the new installation.
To do this, I installed ESXi 6.0 Update 2 into a VM on a newer Mac running VMware Fusion, and using the physical disk from the Mac Pro. The physical disk may be attached to the newer Mac using any attachment method (USB, etc). I have a Thunderbolt SATA dock that I used. VMware Fusion does not let you attach a physical disk to a VM from within the GUI, but it can be done.
After creating the VM, attaching the physical disk, and booting from the ESXi ISO image, I installed ESXi, choosing to completely erase and use the entire physical disk. After installation, you may wish to do like I did and boot up the VM before you replace the EFI files. The reason is so that you can set up the management network. By setting this up in advance, you can run your Mac Pro headless, and just manage it from the network.
After you have installed ESXi in the VM onto the physical disk (and optionally set up the management network options), shut down the VM, but leave the physical disk attached. Go to the Terminal, type “diskutil list” without quotes, and look for the partition that says “EFI ESXi”. Make a note of the identifier (it was disk4s1 in my case). Enter “diskutil mount /dev/disk4s1” or whatever yours may be.
Use the files included in the ZIP to replace:
Then unmount the physical disk with “diskutil unmountdisk /dev/disk4” (changing 4 to your actual disk; don’t specify the individual partition). Then connect the disk to your Mac Pro, power it on, and have fun.
By having ESXi installed on a Mac Pro, you are able to install OS X virtual machines without requiring the VMware Unlocker workaround. Additionally, with four PCI-e slots, you could add things like Fibre Channel HBAs, multi-port NICs, USB 3.0 cards, etc.
The downside to using a Mac Pro 1,1 or 2,1 today, though, is its power usage and heat output. This is due to two primary factors: the CPUs and the RAM. Both are considered horribly inefficient and power hungry by today’s standards (but what do you expect with 10-year old technology?). The two CPUs each have a TDP of 150W. Nearly all of the Intel Xeon CPUs produced today (even the most expensive ones) run much cooler than this. The other culprit is the DDR2 FB-DIMM RAM.
To provide some perspective, I plugged in my handy Kill-a-Watt to see what kind of power was being used. I thought the bulky X1900 XT video card that came with the system would be a large part of the equation, but that turned out to not be true. With the video card, 32 GB of RAM (8x4GB), and a single SSD, the system consumes about 270W idle! Take out the video card, and it idles at 250W. Take out 24 GB of memory (leaving two 4GB sticks installed), the power drops to 170W. So that means the FB-DIMMs alone consume about 100W altogether. I calculated that where I live, it would cost about $1 a day in electricity to keep it running 24/7.
For perspective, my main server, which houses two quad-core Nehalem Xeons (which are about 7 years old as I write this), 48 GB of RAM (6x8GB DDR3 DIMMs), and 12 hard drives, uses a total idle power of 250W. A typical modern desktop PC probably uses less than 100W.
Another potential disadvantage is the Mac Pro 1,1 and 2,1 has PCI-e version 1.1 slots, which are limited in bandwidth to 2.5 GB/s per lane. This may or may not be an issue, depending on the application, but don’t expect to be running any new 32GB FC cards with it.
Possibly the most serious disadvantage, especially with regards to lab usage, is that the CPUs in these model Macs, while they do support Intel VT-x, they do not support EPT, which was introduced in Intel’s next microarchitecture, Nehalem. EPT, Extended Page Tables, otherwise known as SLAT, Second Level Address Translation, is what allows for nested hypervisors. This means you can’t run Cisco VIRL on these model Mac Pros.
So for me, reviving the old Mac Pro is good for lab purposes, and I turn it off when I’m not using it to save electricity. It seems more fitting to me to use the technology in this way, rather than for it to simply become a boat anchor, though it would certainly work well in that application, as the steel case is quite heavy!