Cent OS, Linux Mint, Ubuntu and OpenSolaris on a Ext. USB HDD

phrontiste used Ask the Experts™
Hello Experts,

Is there a way I can install (NOT on the same disk or at the same time):

a) Cent OS
b) Ubuntu
c) OpenSolaris
d) Linux Mint

The above Operating Systems on my External USB Hard Drive ; basically I don't want to disturb the OS I have on my machine due to various reasons and can't risk dual boot ; I have successfully dual booted all of the above on my previous machines but was just thinking if this is possible to have either or all of them on One External USB HDD

If there is a way to install them onto a ext usb hdd and boot off that usb hdd (system supports usb boot) that would be great.

I tried doing once, but when I came to the screen where it says to install grub on, i was confused (not knowledgeable about grub commands or config settings)

Any Help would be appreciated

Also, I read some where that you can have a full workin linux on usb pen drive ? can we do this with open solaris ?

A how-to or step by step would be very very helpful.

Thanks and Regards
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You can install any of the OS's you've mentioned above over the USB disk. But if you don't want to disturb the existing partitions I'll suggest you to physically disconnect your hard disk before the installations. Otherwise most of the installations will likely tr to modify your existing hard disk partition.

Also since you don't want to modify your existnig hardware anyway you need to disconnect the dirve whenever you want to boot from your external disk.

As you see though it is possible it is not very practical to run the O/S over external USB disk. I'll suggest you to install VirtualBox or VMWare and go for Virtualization and then you'll be able to launch your guest whenever you need to experiment and will not trouble your disk partitions too..

Syed Mutahir Alibinarybonsai

Thank you for your reply,

I understand the consequences and the options available, can you please provide instructions on how to install on a external usb hard drive ? the install goes fine, its the boot loader config I want to have on the USB disk so whenever I attach the usb disk / key and set my machine to boot off USB, grub loads and loads the OS (linux, opensolaris) and my windows hard drive is not in contact.

Thanks and regards
Kerem ERSOYPresident
Ok the thing is if your itenal harrdisk is attached during the install the install would go fine but only it would modify your iternal hard disks. MBR which is not what you want. So my instructions will be:
 - Remove your hard disk pyysically
 - Attach your USB disk
 - Reboot from the CD and install the OS
 - You will have a bootable environment there as soon as you don't have your internal Disk is plugged in.

This is it. In fact this is the only way if you dont want your MBR or OS partition gets modified.
But as I've told you before this is not practical..

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Hi KeremE,

I understand what you are suggesting and I knew that - as this is the most straight forward way to do it.

What I want and which is why I asked the question is :

Hard drives are connected (internal and the external usb)
I install cent-os or any other distro, select the approrpiate usb disk partitions, format them, then in advanced mode i select "Grub to be installed on the External USB HDD" - then when it completes, I select USB Boot

But it won't boot
any thoughts on this ? I am not installing the linux bootloader (grub) on my internal hard drive ? just so i have a completely seperate disk for linux.

I can't disconnect the drives all the time as may be I want to do this on my laptop.
your help is appreciated

PS : Thanks "mutahir" for posting the comment for me
Kerem ERSOYPresident
The thing is: The CentOS and RedHAT installation directly modifies the existing GRUB. There's no way to intervene this. This is why I've suggested you to remove the disks and setup the USB. In the past I've tried this on my own and it resulted in an unbootable harddisk isnted of the grub modified over the USB.

So this is the only way to accomplish what you ant. After all I am not writing the code all I could tell you is how does it function properly and this is how it would run properly.

Kerem ERSOYPresident
> But it won't boot
> any thoughts on this ? I am not installing the linux bootloader (grub) on my internal hard drive ? just so i
> have a completely seperate disk for linux.

The problem here is as I've told earlier it tires to modify the GRUB on your hard disk first if it is present. This is why I've suggested the removal olf the hard disk during the installation.

Then you ned to change the boot order to allow USB device boot before the HDD boot.


Not exactly what I had wished for :-) but helped

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