2011 Mac Mini Server Disassembly / Raid-0 SSD Upgrade
(This is a summary from my Mac Mini SSD RAID-0 Project, see the set for more photos and a video.)
[ General disclaimer: These are my findings posted for the curious, you do all of this at your own risk, don't blame me if stuff breaks etc. ]
Holy crap, I don't want to ever have to do that again. Hopefully, it still works when reassembled with 8 GB of RAM and dual SSDs. In theory, it just might work. (Update: I now feel comfortable with this after tearing down and rebuilding a few times - and two weeks' of running time later, no problems.)
Yes, this whole operation is somewhat frivolous. The stock dual 7200-RPM 500-GB 2.5" drives will themselves be configured as SPAN and in an external enclosure, driven via Firewire 800.
Not in the frame: Mainboard.
Tools used: Torx T6 and T8 screwdrivers (and, I think, a Philips #00) and a Dogfish Head 90-minute IPA.
I referenced a teardown guide from ifixit for the "steps" and post-it notes, so I could remember what went where when reassembling. (Note: not all steps apply, you don't need to disconnect the bluetooth module etc.)
For the hard drive removal / upgrade process, this OWC video was handy and has rather hilarious background muzak. Note that there are different videos for server vs. non-server models.
Don't bother with the crappy $5 screwdriver "kits" (eg. the blue and green ones by the RAM in this photo) - go to your local hardware store (or online) and pay the $6 or whatever it might cost per tool for quality Torx T6, T8, and (if needed) Philips #00 screwdrivers. One of the cheap ones, in one case, didn't fit one fan screw I was trying to remove. However, the so-called plastic "spudger" tool did come in handy for pulling up cables and nudging other things where fingers wouldn't reach, and where metal was not a good choice to use.
Removing the "mainboard"
The OWC video suggested you should put screwdrivers into holes on the mainboard, and pull back; this seems like a great way to break or snap the PCB and/or accidentally ruin traces along the way. I tried pulling several times, but it seemed that no amount of careful force would budge the thing.
Instead, I turned the mini around and carefully pushed the heat sink / vent outward using my thumbs, and with a little pressure, was able to pop the board out. The heatsink is just behind where the screw holes are shown in the video, toward the connector plate. It is pretty tight as the plate (where all the USB + power connectors etc. are) has snaps/clips on either end holding it in, but it does eventually give.
Once you get the mainboard, the rest is easy. Don't pull the board fully out until any attached power cables etc. have been disconnected - and once the board is out, you can take out the power supply and HD chassis.
I also recommend booting the computer upside-down and with the bottom cover off once after reassembling, just to make sure the fan starts up; I noticed that mine didn't at first(!), because the tiny fan power connector was not fully-seated on the mainboard when I put it back in. No fan would've meant a toasted CPU at some point, so make sure you check that. Use a flat plastic tool or something to push the connector flush with the board, to ensure it's seated nicely.
Also, there's a bit of a trick with the wireless module / antenna / grill assembly when popping it out and in - I think it slides underneath into place, so keep that in mind. Similar moves apply to the black plastic cowling at the bottom left near the fan. Sometimes things need a little jiggling to get into place.
Re-installing Lion: ⌘-R / Internet Recovery FTW
On mid-2011(?) Mac hardware, push and hold Apple-R (⌘-R) during boot to kickstart the Lion Recovery mode, with wifi or an ethernet cable connected. It'll attempt to boot from a Lion recovery partition normally installed, and when that fails, it will magically go out on the Internets, and download and install and boot the recovery partition. That will run and after disk set-up and partitioning etc., another download of up to 7 GB (at least, according to my router's traffic for that day) will happen, Lion will install, reboot, and voila.
Partitioning the SSDs, overprovisioning and stripe block size
From what I read online, it was recommended to leave up to 20% "unpartitioned" empty space for "overprovisioning" with an SSD to help with performance (garbage collection) and reliability. I got two OCZ Vertex III 60 GB SSDs, and using the disk utility built into the Lion installer, set them up with two partitions: [ 48 GB ext3 / 12 GB empty space ]. As for stripe block size, I had heard 64 KB or 128 KB as general recommendations, so I used 128.
With SATA 3.0 (up to 6 gbps) and SandForce 2xxx controllers on the OCZ SSDs pushing up to 550 MB/sec read rates, I was able to get 1000+ MB/sec on larger files in benchmarks.
RAID-0 pros/cons: Worth it, or is one SSD enough?
- Wow, up to 1000 MB/sec. That is a shiny number.
- If one drive goes south, you lose everything.
- In most cases, 1000 MB/sec is a theoretical maximum you'll hit only in benchmarks. Small bursts may be more realistic, and in most cases with less-compressible data, numbers will be much lower (albeit, 250+ MB/sec or whatever is still nothing to sneeze at.)
If you're a tinkerer / overclocking fan and don't fear the risk of data loss (i.e., you make time machine or image backups), RAID-0 is worth trying just for the fun of it. Otherwise, I think one SSD alone makes a huge difference in responsiveness given near-zero seek times etc., and with theoretical maximums of 500 MB/sec, that's plenty of I/O for just about anybody.