Need help on booting OS X through external HD

Discussion in 'Mac Basics and Help' started by dschiller, Jun 12, 2007.

  1. dschiller macrumors regular

    Joined:
    May 7, 2007
    #1
    Hi all

    I am about to buy a Seagate FreeAgent Pro with 500Gb and FW400/USB2.0/eSATA. I have a Mac Mini, and its internal HD is too small for me (80Gb total for about 70Gb of data).

    What I'd like to do is install OS X on the External HD and use it as my main boot drive, and perhaps the Mini's internal HD for data backup. Would that be possible/legal (I only have the install discs that came with it - my first Mac:D )? If it is complicated, could you guys recommend me a tutorial?

    I'd also like to know whether the performance would be better or worse. The Mini's got a 5400 RPM drive, and the external is 7200 RPM and would be connected through FW400 (plus a lot of free space for now).

    One last question: if it is indeed possible/legal to use the External HD as my main boot drive, would it be possible to install and boot Windows on the external HD using Boot Camp/Parallels?

    Cheers
    Daniel
     
  2. MikeTheC Guest

    MikeTheC

    Joined:
    Apr 26, 2004
    Location:
    Gallifrey -- Capitol City, Prydonian Sector
    #2
    Can't speak to Boot Camp, but you can certainly set this up as your primary HDD if you like. So long as it's attached to the Mac via FireWire, it will be an option for you.

    FireWire with a SATA drive should give you some amazing speed. I have a SATA 80GB connected to my PowerBook G4 via USB2, and while I can't boot from it, it's nice and fast to play music and video back from, and probably would be awesome to record them to it. I really don't do that sort of work myself, but typically professionals all use FireWire as their bus of preference, and naturally SATA/SATAII drives are pretty darn fast.
     
  3. dschiller thread starter macrumors regular

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    May 7, 2007
    #3
    So you're saying it is possible to make a full install of OS X on the External HD using just the Install Discs that came with my Mini?

    BTW, thanks for the quick reply!

    Cheers
    Daniel
     
  4. dschiller thread starter macrumors regular

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    May 7, 2007
  5. EHUnlucky7x9@ao macrumors 6502

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    Jan 8, 2006
    Location:
    New Jersey
    #5
    yes, you can install OSX onto your external. Pop in your install discs... when you go through the setup, make sure you choose the external. Make sure the external is formatted as OSX Journaled. After you install it on your external, it will be the bootup drive after it restarts.

    When you shutdown, it won't be the main start up drive though. You would have to hold T down when turning on your Mini in order for you to choose which boot up drive you want.

    2 ways to overcome it is to erase the OSX volume in your mini.... or go to system pref>startup drive>choose the external HD volume. Restart. That should make it permanent. If not, the getting rid of the OSX volume on ur Mini's internal will fix it. You have to keep a drive with the OSX volume plugged into the mini at all times to work.

    OSX searches the internal drives, then the USB ports and firewire for any OSX Volumes.
     
  6. dschiller thread starter macrumors regular

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    May 7, 2007
    #6
    Is performance going to change (to better or worse)?

    Thanks
    Daniel
     
  7. EHUnlucky7x9@ao macrumors 6502

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    Jan 8, 2006
    Location:
    New Jersey
    #7
    Depends on your Mac Mini... is it a Core Duo Mini? Those have SATA internals.
    You'll see that it's the same performance for the most part...but there will be a slowdown at the more intensive data stuff like editing video. Your going to consider the input and output of data between the CPU and the HD...which will be your external and that gives 480MB/s If it's internal, you would be working with 3GB/s. A big difference.

    If its a G4 Mini... then it has the PATA HD... You'll see faster speeds. The read/write on those HD's were 100MB/s.
     
  8. dschiller thread starter macrumors regular

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    May 7, 2007
    #8
    I got a Core Duo Mini... Well, I guess I'm not gonna be able to do what I wanted then.

    Anyone can think of a way I can have both a full backup of my stuff (in case the main boot HD goes bezerk) AND a full-speed main boot drive that isn't almost totally full just using the 80Gb Mini and the 500Gb External HD (with about 70Gb of data)?
     
  9. Satch macrumors newbie

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    Jan 21, 2007
    Location:
    The Netherlands
    #9
    I'm sorry but you've got it pretty wrong.
    The speeds that you are talking about are no indication for the read/writing speed of the hard-disk. It's just the highest possible read/writing speed (to say it simple). The speed that the link between the hard-disk and motherboard can handle. Most of the 3,5" hard-disks are around 50-60 MB/s and laptop hard-disk are around 40 MB/s.
    So you will get a speed boost with an external 3,5" hard-disk. :)
     
  10. dschiller thread starter macrumors regular

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    May 7, 2007
    #10
    Are you sure about this? That'd be great news! :D

    Can anyone confirm this?

    Cheers
    Daniel
     
  11. jtown macrumors 6502

    Joined:
    Jul 3, 2003
    #11
    Just to clarify, SATA vs. PATA is irrelevant. The drive mechanisms are identical between SATA and PATA versions of the same drive. Neither interface is the bottleneck during data transfer. Test two drives of the same model with SATA and PATA interfaces and you'll find no statistically relevant difference outside of a few very isolated situations. (SATA has a few enhancements like NCQ which could give it a very marginal edge in some areas.) The only SATA drives that consistently outperform PATA drives are the Western Digital Raptor drives. Of course, those are 10,000 RPM drives which are built off their enterprise SCSI drives so it's not a comparison of interfaces but drive mechanisms. They're also very expensive and have relatively low capacities.

    You will, however, see a noticeable difference in performance between "equal" 2.5" and 3.5" drives. A 7200 RPM 3.5" drive will generally outperform a 7200 RPM 2.5" drive. (Again, SATA and PATA are irrelevant.) You will also see a difference between USB2 and FW400 connections. FW400 will outperform USB2.

    So, in a nutshell, get a decent quality 3.5" firewire hard drive for the best possible performance.
     
  12. plinden macrumors 68040

    plinden

    Joined:
    Apr 8, 2004
    #12
    Well, this is definitely possible if you want to go this way. Using Disk Utility, partition the external drive into two, a bootable 80GB (or smaller - a full OS X install takes about 14GB but you need a bit extra on top, so 20GB is about the smallest) and the rest for data. Insert the installer DVD and reboot holding down the C key. You will boot into the installer. Choose the external HDD partition and go through the install process. You can customize the install to cut down on applications you won't use (e.g. not everyone uses GarageBand).

    After this, you will have a bootable partition on your external HDD. You can do things like setting your iTunes library location in both the internal and external boot drives to be on the larger data partition. This way, you'll have an alternative boot disk if the internal HDD crashed, with full access to the same data.

    However, you really need to think about proper backup. If you have data you really want to keep, it needs to be in two different places (NOT two different partitions on the same disk), since the external HDD can crash just as easily as the internal drive.

    An alternative to installing is to use something like SuperDuper! to clone your Mini's HDD to the external drive. I'm not sure if SuperDuper! will clone to a partition (the process involves erasing the destination disk before copying), but it would definitely copy a fully bootable copy from the Mini. Although you have to pay to get all the features, the free version allows cloning.
     
  13. dschiller thread starter macrumors regular

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    May 7, 2007
    #13
    I'm not sure I understand what you are suggesting. After doing the above, which boot partition (internal or external) would I be using as my main one? If it's the external, wouldn't it be slower? If it's the internal, I'm still going to be mostly booting from a drive which is almost full.

    I know this. That's why I asked if there was another possibility :)
     
  14. plinden macrumors 68040

    plinden

    Joined:
    Apr 8, 2004
    #14
    It would be faster to boot from the internal drive. But this is what I do: anything I don't want to lose (photos, purchased iTunes tracks etc) I keep on both my internal drive and on an external drive and burned to DVD that I keep in a drawer at work.

    Anything that I can afford to use (backup rips of DVDs I own, downloads etc) I just keep on the external drive, even though it would be a pain to re-rip everything. I also have a bootable partition on my external drive. This has been useful for us, allowing my wife to continue using her MacBook until the Apple Store was able to replace a failed hard drive.

    The real speed difference between an external and internal drive is in something that reads or writes a lot of data to disk. You're not really going to notice any difference watching a TV show or viewing an iPhoto library. You might notice a slow down ripping a CD to an external drive. But unless you're doing something like encoding real time video the speed difference really isn't going to be an issue for you.

    Putting your essential data on your internal drive, with a copy on the external drive, plus a bootable external partition, means you can keep the HD usage down, while also giving you an alternative boot until you can get any problems sorted out. And remember, your hard drive is going to fail, sooner or later.
     
  15. dschiller thread starter macrumors regular

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  16. EHUnlucky7x9@ao macrumors 6502

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    New Jersey
    #16
    You sure about that? :D

    Well, at least the answer of the external being faster was right.
     
  17. dschiller thread starter macrumors regular

    Joined:
    May 7, 2007
    #17
    I've been thinking about this, and perhaps I should buy 2 of these and this external enclosure. That way, I'll have two separate drives for backup (in case one of them goes wrong) and I won't have to keep my data on the Mini's internal HD (which will become my main boot drive). The day I actually need 500Gb storage, I simply move a jumper on the enclosure and I get a RAID 0 Configuration with 500Gb. It will be U$60 more expensive than the FreeAgent Pro with 500Gb, but I get the expandability and I think it solves my problem. What do you guys think about this idea?
     

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