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Workflow for HDD testing, imaging

Hi John,

I've been working on a small-scale refurbishing operation and would love you hear your input on how to efficiently test/defrag/image multiple HDDs at once. The least efficient way I've been using is to do it all within Apple's disk utility, one at a time. I'd like to set up a USB array to do disk health testing on used drives, then drop an updated image to, say, 5 drives simultaneously. Do you have a particluar hardware & software setup that works (or any that DON'T work) well for this purpose?



  • Hi Aaron! Thanks for the post!

    I do most of that the low-tech way, so I might not have a great answer for you. :-)

    From visiting a lot of recyclers, I've gotten the impression that the larger hardware/software systems that securely wipe 20 drives at once tend to be on the PC side. Even if they deal with Macs, they tend to have a PC system to wipe drives. And most of my drives come from recyclers that are required to wipe and test their drives before handing them over to me, so it hasn't been a huge issue on my end. In terms of data security, I believe that dumping an OS is generally enough...that's a controversial view, but an OS dump does a quite a bit of writing, and I have to think the chance of someone spending all day doing data recovery on one of my laptops in order to retrieve small slivers of data is EXTREMELY slim.

    As I may have mentioned, my technique is to boot from an external USB SSD drive, and on the desktop of that drive I have SuperDuper, as well as all my OS images. In SuperDuper I pick the OS image on the left side, the internal hard drive on the right side, click OK, and in 10 minutes you're done. It's a pretty quick and flexible method. I produce 5-30 machines a day, and tend to image them as part of the process of building them, so imaging tends not to be the bottleneck. In fact I boot to the external and image the drive when I am first checking out a machine -- it's a good way to kick the tires. While the drive is imaging I'll test all other functions.

    I have seen an Apple server-based basically connect 10-20 machines via ethernet, it powered them on via wake-on-lan, it then ran the appropriate ASD (Apple Service Diagnostic), then it securely wiped the drive, then dumped the OS. So you could connect 20 machines, walk away for a couple hours, come back, and either the machines are done, or maybe 1-2 have an ASD error. So that kind of setup is possible, although it's not feasible for me, and I've found that network-based systems tend to degrade over time as well because people forget how they were set up, new hardware is released, etc.

    In terms of diagnostics, the ASDs work well if you can find them, but there is one ASD per model laptop, which means you're dealing with lots of DVDs. When I care enough to use diagnostics I use TechTool Pro, which is FAR better than Disk Utility, and it also has secure wiping tools, and a lot of other stuff. It's made for one drive at a time though, unless it has scripting abilities that I'm not aware of (and it might). You could also put TechTool Pro on the same external drive you use for imaging so that you can do everything in one pass.

    Generally I like to let the hardware prove itself to me rather than use diagnostics. I have a fairly rigorous testing procedure, and I also burn in machines for 6-8 hours, so if a drive is failing it tends to let me know by taking too long to image, making noise, failing to boot the OS, getting way too hot, etc. I know that's a little sloppy, but it's always worked for me, and my failure rate is better than average.

    Anyway, I hope that sort of helps! :-) If I ever have 1000 working machines I might be inspired to improve my situation, but for now my pile of external drives is quick enough for my needs, and pretty flexible.



  • Thanks a ton John, as always your answers are incredibly thorough. I'll definitely test out your method with an external drive and SuperDuper since you're not noticing a bottleneck.

    Regarding OS versions, which ones do you keep images of? I'm assuming you have a bootable external drive with Lion or Snow Leopard for older machines, and another version for newer ones?
  • Exactly -- my boot drives are either Snow Leopard or Yosemite. I do get some older machines that won't boot to Lion, so Snow Leopard is preferable (and it boots way faster than Lion). And then on the upper end it's very rare I get a laptop that came with a newer OS than Yosemite, so it works out well.

    As far as what I dump down to the machines, I have images for all the OS versions, up through El Capitan. It gets tricky when a new OS comes out to find a "clean" version that is not associated with an iCloud ID, and I've yet to look around for a usable copy of Sierra.
  • I wonder if completely removing your Apple ID from a machine after updating to Sierra would render the install "clean" - unless they bake that ID into the install
  • Probably, but I'm a little paranoid and unwilling to risk it. I don't want to ship 100s of laptops potentially connected to my ID in some way. :-)
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