Run Mac from USB

[montu_n23]

All, a question here thats bogging me.
PLease do not ask my why I did so, I did so for various reason.
I wiped the MAC clean of the OS Lion and installed Windows 7 pro 64 bit. all of 500 GB for Windows.
I tested internet recovery, so anyday if I want to get back to MAC OS, I can use internet recovery and reinstall MAC OS.

My question is - while I have 500 GB full of Windows, is there a way I can run Mac off of a USB drive?

I was thinking of using a 32gig USB drive, use internet recovery, and install OS on the flash drive using disk utility. But I am concerned about this, with all of 500 GB dedicated to windows, when I use internet recovery, where would it store temporary files if any. Would it save temp files on the 500 GB hard drive? of so, that would hurt my windows installation. If it does not, is the mac accessing everyting everything fro the server directly? and is not using ANY storage on the MAC itself until we get to and choose an option on Disk Utility?

My objective is, when I start MAC, I want to be able to choose either of two OSs to booot
1. Windows on the 500 gig drive
2. MAC OS from 32 gig flash drive (basically for any firmware updates)

Any suggestions on how to go about this? is internet recovery a good bet (that it wont mess around with windows partitions unless I choose windows drive for installation from disk utility)?

much appreciated.

Thanks
MN

 

[Weaselboy]

I have never tested your exact setup, but I know Internet recovery works even with a new and unformatted drive, so I don't see why your suggestion would not work. I know when you do Internet recovery with a new drive the installer downloads to memory as a DMG file then mounts that DMG (disk image) to run the installer.

 

[montu_n23]

I know when you do Internet recovery with a new drive the installer downloads to memory as a DMG file then mounts that DMG (disk image) to run the installer.

Downloads to memory - this is my concern - would it download it to the primary 500 gig drive? if it does, that will mess around with my windows installation

 

[Weaselboy]

Downloads to memory - this is my concern - would it download it to the primary 500 gig drive? if it does, that will mess around with my windows installation

No.... by memory I mean RAM.

 

[DeltaMac]

Another way to look at your situation:
OS X, and your OS X installer, by default, can't write to a NTFS-formatted drive.
So, the OS X install won't touch your Windows installation - standard OS X setup can't modify it.
All you need, when you boot to internet recovery, is to point to your flash drive as the destination.
A new 32GB USB flash drive will not likely come out of the package with a Mac format, so you would want to erase the flash drive first, using Disk Utility (also available while booted to Internet Recovery), so the drive is configured as GUID, and set for a MacOS Extended format.

 

[montu_n23]

Another way to look at your situation:
OS X, and your OS X installer, by default, can't write to a NTFS-formatted drive.
So, the OS X install won't touch your Windows installation - standard OS X setup can't modify it.
All you need, when you boot to internet recovery, is to point to your flash drive as the destination.
A new 32GB USB flash drive will not likely come out of the package with a Mac format, so you would want to erase the flash drive first, using Disk Utility (also available while booted to Internet Recovery), so the drive is configured as GUID, and set for a MacOS Extended format.

Thank you for clarifying this - I assume I will need to format the flash drive - "extended Journeled" format?

 

[Weaselboy]

Thank you for clarifying this - I assume I will need to format the flash drive - "extended Journeled" format?

Yup.

 

[montu_n23]

Worked like a charm..running OS from USB drive..but it runs like C***
I am guessing 16 gig drive is not sufficient..I have never seen a mac hang..will try the install on a 32 gig drive and see how that works.

 

[Weaselboy]

Worked like a charm..running OS from USB drive..but it runs like C***
I am guessing 16 gig drive is not sufficient..I have never seen a mac hang..will try the install on a 32 gig drive and see how that works.

Yeah... that could be part of the problem. Between the OS and swap/cache files I think you are pushing it with 16GB. Are you on a newer Mac with USB3?

 

[Samuelsan2001]

Worked like a charm..running OS from USB drive..but it runs like C***
I am guessing 16 gig drive is not sufficient..I have never seen a mac hang..will try the install on a 32 gig drive and see how that works.

No it's down to the speed of the flash modules in a standard USB drive if you want to get good speeds you'll need an external hard drive or a better quality USB stick.

Something like this

http://www.amazon.co.uk/SanDisk-Extreme-Flash-Drive-245MB/dp/B00DZPUOU8