How to set up external SSD as Boot Drive for new iMac

capone007 said:

Hi,

I just got my new iMac 27" and want to set up an external SSD drive as my boot drive. I didn't get the Fusion Drive. I have an external 480GB SSD in a USB3 enclosure from OWC to use as the boot drive. I'm just not sure how to start or what to do. Can someone explain or send me a link on how to do this?

Thanks for any help you can provide.

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Use Carbon Copy Cloner to clone your internal drive to the external. Then you can boot from the external.

You can use version 3.5.1 ($40) or 3.4.7 (free, and works well on OS X 10.6, 10.7 and 10.8).

capone007 said:

Thanks for the info...just a quick question. Once I clone the internal drive and put it on the external, do I need to wipe the internal drive?

Thanks!

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You don't have to wipe the internal unless you want to. You can set OS X to startup from e external an bypass your internal if you want. It will still be recognized as well to write/read from as well. The only problem that you will run into is the internal an external will not mat h unless you continually sync them with CCC.

capone007 said:

Is it a big deal if the internal/external aren't synced...or should I sync them often?

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That depends on how you plan to use your internal drive. Do you plan to boot from both drives? If so, why? It helps if you explain what you're trying to accomplish and why you want to boot from an external drive.

If you're using the external only as a bootable backup, you should backup with enough frequency to minimize data loss in the event of a problem.

Just to post an alternate method, which is what I did with my external thunderbolt SSD, is to just boot from the internet recovery partition on the internal HD, then select the SSD as the install location when you choose to install OS X.

This will mean you have to download the bulk of the installer (about 3 to 4 gigs), so be aware if you have a slow connection or live in 1995 and have a data cap.

joe-h2o said:

Just to post an alternate method, which is what I did with my external thunderbolt SSD, is to just boot from the internet recovery partition on the internal HD, then select the SSD as the install location when you choose to install OS X.

This will mean you have to download the bulk of the installer (about 3 to 4 gigs), so be aware if you have a slow connection or live in 1995 and have a data cap.

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Unfortunately, that method doesn't copy the user-installed apps or data at all. It only creates a bootable drive, which the OP would have to re-configure, reinstall apps, copy data, etc. Cloning is a much quicker and more reliable method if the OP wants to keep their existing environment while booting from the external.

capone007 said:

Not trying to boot from both drives...only the external. I'm using the external SSD because it will be faster than the fusion drive with 3x more space than what the iMac internal offers. I need quite a bit of space because some of my App libraries are huge. So I'm not using the external as a bootable backup just the main booting drive.

Thanks again.

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I doubt you'll see any performance improvement booting from the external vs the internal fusion drive. As the fusion drive is optimized, system-related files would be located on the internal flash memory, making boot times very fast. I think you're better off booting from your internal drive and move some of your large data files to the external.

Configuring External Boot Drive

Like the OP, I'm setting up my new Mac Mini with an external SSD drive via Thunderbolt (Samsung 840 550GB + Seagate Thunderbolt Adapter), plus I want to use a second external HDD (Seagate Back Up Plus 4TB) connected via USB 3.0 to store non-OS data (photos, music, documents, downloads, etc.) Would anybody mind clarifying what must go on the external boot SSD and what goes on the external HDD?
I've done this before but think I got got some of it mixed up.

GGJstudios said:

I doubt you'll see any performance improvement booting from the external vs the internal fusion drive. As the fusion drive is optimized, system-related files would be located on the internal flash memory, making boot times very fast. I think you're better off booting from your internal drive and move some of your large data files to the external.

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Another thing you can if you're concerned about what goes where, is to "split up" the fusion drive. That's what I did; system, apps and data I need high performance for are on the flash drive, everything else is on the 1TB mechanical drive.

It's easy and risk-free, instructions are here:

http://www.macworld.com/article/2015664/how-to-split-up-a-fusion-drive.html

Of course you need to back up your data first.

zorinlynx said:

Another thing you can if you're concerned about what goes where, is to "split up" the fusion drive. That's what I did; system, apps and data I need high performance for are on the flash drive, everything else is on the 1TB mechanical drive.

It's easy and risk-free, instructions are here:

http://www.macworld.com/article/2015664/how-to-split-up-a-fusion-drive.html

Of course you need to back up your data first.

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Thanks but this seems to apply only to an Apple Fusion drive. I'm not using theirs. I'm using two separate drives: One SSD. One HDD.