Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

Summary: Following Apple's calling it quits on the Xserve in January, Mac managers have by necessity been creative to fill the void. A tip shows that it's possible to build a Redundant Array of Independent Servers (RAIS) that takes advantage of the new Mac mini's ThunderBolt port and the Target Disk Mode long built into the Mac OS.

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TOPICS: Servers, Apple, Hardware
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Following Apple's calling it quits on the Xserve in January, Mac managers have by necessity been creative to fill the void. A tip shows that it's possible to build a Redundant Array of Independent Servers (RAIS) that takes advantage of the new Mac mini's ThunderBolt port and the Target Disk Mode long built into the Mac OS.

On the AFP548.com site in February, contributor Josh Wisenbaker suggested using a Mac mini RAIS as a way to increase redundancy for a low-cost server setup.

Take one Mac mini server configure as you like and enable its boot drive as a RAID member. Boot the other Mac mini server into Target Disk Mode. Connect them with a FW-800 cable (or ThunderBolt cable if the equipment supports it). Add the TDM mini to the mirror that the boot drive is in.

Target Disk Mode is a long-standing feature of the Mac that lets you connect a pair of Macs and use one as a hard drive. It's the easiest and fastest way to upgrade systems. It used to be called SCSI Disk Mode, that's how long it's been a part of the Mac.

Precursor Systems, a Mac consultancy based in Winnipeg, Manitoba, has maintained a page on the RAIS concept. Founder Alex Narvey posted on Monday that he had tested the system running Lion Server and SoftRAID 4.07 ($129), third-party Mac RAID software by the eponymous SoftRAID LLC.

In an interesting tip, Narvey suggested using the ThunderBolt port for one mirror and the FireWire 800 port for a second Target Disk Mode mirror. SoftRAID supports this.

With SoftRAID you can even add ANOTHER mirror. So if you have used the FireWire port for your TD Mac mirror you can add a USB/FW800 drive to the USB port, make it a mirror and then if one computer or the other blows up you can send it off for repair and replacement and maintain a mirror all the time just by popping that USB drive into the empty FireWire port (for best performance of course).

(With the new Thunderbolt minis your FireWire port would be available for the external drive all the time.)

Narvey compares a restore using Apple's software RAID and SoftRAID. Check it out.

Topics: Servers, Apple, Hardware

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  • RE: Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

    Apple will soon ditch everything that doesn't run the iOS / OS X hybrid that is coming. Optical drives will be gone and any desire for retail boxed software or Bluray support is already gone.
    slickjim
    • RE: Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

      @Peter Perry

      How does this relate to a story on redundant servers?

      Optical drives are basically gone now, the Mini server dropped them a while back.

      Lion server isn't boxed, but this doesn't change the server redundancy situation.

      Blu-ray has never been a server issue.

      Mac Minis are no more or less able to run any UI features than any other Mac. Since the underlying OS in iOS and OS X is the same I don't understand your point.
      richardw66
  • Who Needs Target Disk Mode?

    We have an easier and faster way to upgrade systems: it's called "apt-get dist-upgrade". And the nice thing is, the system keeps running while you do the bulk of it.
    ldo17
    • LOL

      @ldo17 apt-get upgrade hose-my-machine
      zmud
      • Re: apt-get upgrade hose-my-machine

        @zmud You must be thinking of Microsoft Windows. On Linux, it just works.
        ldo17
    • RE: Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

      @ldo17

      Hmmm - you are suggesting that your upgrade command somehow makes a RAID array irrelevant?

      Does your update command magically prevent hardware failures and disk corruption?

      Yet another point that shows Linux shills don't understand what computers are used for!!!

      And yes I have used Linux for some very serious serving, and it does have a plce for that, it is the stupid blogging I am commenting on.
      richardw66
      • Re: Who Needs Target Disk Mode?

        @richardw66 "you are suggesting that your upgrade command somehow makes a RAID array irrelevant?"

        Read the subject line again.
        ldo17
      • RE: Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

        @ldo17 - first, the name fits quite well. Second, did you even read the story? It's not about upgrading the installation from command line or GUI, it's about a redundant array of servers.

        Let me break down how TDM on a Macintosh works - it turns that Macintosh into an external hard drive for another Macintosh. Going a step further, it allows access to all internal drive on one Mac from another (using TDM on my old PowerMac G4, I was able to use its internal optical drive to install OS X Leopard on a PowerBook G4 which had a failing optical drive).

        So with what Jason described here, we're not talking about upgrading your Linux server (which will probably be hosed, anyway; "dirty" upgrades aren't always a good idea with Linux). We're talking about mirroring entire servers in a similar fashion to how you'd normally mirror hard drives, so when one server fails you have another to take its place immediately.
        Champ_Kind
  • RE: Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

    For the price of one Mac mini in this scenario you can build 2 Mac mini Hackintoshes that are more powerful than the real minis. Just sayin you can make a good idea into an even better idea.

    ...Think Different
    Goldie07
    • RE: Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

      @Goldie07 <br><br>Yeah, but I couldn't count on them to run for 8 years.<br><br>Nor could I expect one built in 2005 to have a power consumption of 15-30 watts, depending on load. And know that if/when I replace it then the power consumption will be even lower.<br><br>Yeah I can waste my time cobbling something together, but why not use a well built and efficient machine, rather than trying to pinch intellectual property to save a short term buck, whilst throwing many more bucks at your power utility?

      I am currently looking at power use here, to that end I have a power meter on my Mac Mini as I thought it might account for a slab of our base load, as I have found out it is using next to none of it.

      I had previously retired 2 Mac G4 towers from around 2000, purely to reduce baseload, as they were running perfectly. I sold one as a working unit, and the other has replaced a friend's Core Duo PC, the 450MHz G4 tower works better.

      So why anyone would bother with lower quality hardware running an OS they have stolen is beyond me. Yes STOLEN!!!
      richardw66
    • Thanks, but no thanks.

      @Goldie07 ... When I deploy servers, first and foremost they have to be reliable. A "hackintosh" by its very nature is a hack -- an unsupported workaround.<br><br>While it may be fun to put together a hackintosh to say, "there, I did it!" or maybe even to allow you to run a couple Mac apps every now and then on your Windows PC, it has NO place in a data center. Zero. No IT pro with an ounce of pride in his work would ever risk his (or her) reputation on a hack for anything of even mild importance.<br><br>Besides: Mac Minis are cheap, efficient and easy to setup. The time I'd save by deploying a Mini instead of building a hackintosh would more than compensate for any hardware savings. And the Mini would be supported under warranty and I could get Apple tech support, if needed.<br><br>A Mac Mini server is a no-brainer for situations that need or could use a Mac server.
      jscott69
    • RE: Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

      @Goldie07 Can a Hackintosh support TDM?
      Axsimulate
    • RE: Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

      @Goldie07

      No IT professional that I've known in my 30+ year career would ever suggest using a cobbled together, illegal (see Apple vs Prystar) solution in a corporate environment. Pathetic.
      gribittmep
    • RE: Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

      @Goldie07 Not so much. Hackintosh is about as stable as Jello when it comes to long-term support (Apple changes stuff in the OS that breaks Hackintosh drivers from time to time), and there's to TDM to be had on standard PC hardware.

      So if you add the Time=Money factor to the equation, 3 Mac Minis will end up being much less expensive over a 3-4 year period than 3 Hackintosh computers of any size. Also, you can't mirror entire servers so when one has a hardware failure you have another as a backup.
      Champ_Kind
  • RE: Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

    Cant you just use one mac mini and an external thunderbolt drive?
    Why the extra cost of another mac mini?
    sbscraps
    • RE: Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

      @sbscraps

      This is a sensible question.

      I think for redundancy of the computer hardware.

      Although Mac failures are rare, they do happen, and who wants to be the one whose server dies, and has to wait to go get a new one to get up and running again?

      Redundancy is no use if the one part you have 1 of fails!
      richardw66
    • RE: Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

      @sbscraps
      The goal is redundant servers is so if one mac mini fails you have a second mac mini ready to take over while you get the failed mac mini repaired. This approach allows redundancy for both the server and the data.
      MrMike99
    • Redundancy

      @sbscraps ... As mentioned in the article, if one Mini were to die, you'd have the other (with a mirror of the first's contents, thanks to being a part of the RAID set) to use while the first is repaired or a replacement is ordered.<br><br>But your point isn't a bad one: if you were to use two external RAID sets and two separate Minis, you'd have even more redundancy: One RAID set would be the OS/apps, the other would be the data; and you'd have a spare/backup Mini.<br><br>In the RAIS setup described, there would still be downtime when you fire up the second Mini to act as the replacement server, and you're trusting your OS and data to the same internal drives (granted, two of them: one in each Mini). You would minimize data center space and power consumption -- which are both important.

      But with external drives, you gain some speed, since you can have I/O happening with each RAID set simultaneously and the external drives can be faster; some capacity, since the external drives can be larger; and more flexible redundancy, since you could have a stack of Minis standing by -- or even press a desktop Mini into service as the server, if necessary, just by connecting it to the external drives and booting it off the OS RAID set.

      It wouldn't look as pretty or be as power or space efficient, but it would give some speed and "redundancy" benefits over RAID-ing the internal drives of two Minis, and still only take a reboot (basically) to deploy the "clone".
      jscott69
  • RE: Creating highly-redundant, low-cost Mac servers with Lion Server and Mac minis

    Sonnet has a cool piece of hardware out ( <a href="http://www.sonnettech.com/product/rackmacmini.html" target="_blank" rel="nofollow">http://www.sonnettech.com/product/rackmacmini.html</a>) that allows you to pair up the Mac Minis. The new version (http://www.engadget.com/2011/09/07/sonnet-announces-rackmac-mini-xserver-makes-apple-desktop-it-li/) will add Thunderbolt support with a PCIe slot as well! I am pretty excited to see how this hardware and RAIS work together... it may be interesting.
    hjenkins1