[TriLUG] booting off usbstick

[via TriLUG]

I have successfully created many bootable USB drive with linux  
installed there on using dd. See

https://www.cyberciti.biz/faq/creating-a-bootable-ubuntu-usb-stick-on-a-debian-linux/

If the usb drive is, for example, /dev/sdb, make sure that name is  
used in the command and NOT something like sdb1. The command takes a  
long time to run because there's a lot to copy, so wait for the long  
quiet time to end. This wipes out all info on the drive, so get it  
correct! I have then gone back done such things as shrink the  
partition with gparted and created a fat32 partition to move files to  
an alternate OS.

Good luck

/Roger

Quoting Joseph Mack NA3T via TriLUG <trilug at trilug.org>:

> On Sat, 11 Jul 2020, Stephen P. Schaefer via TriLUG wrote:
>
> thanks for everyone's suggestions, but the task really is to boot an  
> arbitary diskless computer off a usb stick, something that's done  
> routinely with usb sticks with live file systems.
>
> The problem is that I don't know how it's done. Just for fun, about  
> 10 years ago, I tried booting my normal filesystem from a usb stick  
> and got the same results (kernel panic) and gave up.
>
> I'm back trying again. This time, the push is that I want the drive  
> trays for storage, but this is incidental to getting the machine to  
> boot off a usb stick.
>
>> I may be doing something similar to what Joe is trying to do: I'm  
>> running CentOS 8 from an (external) USB stick, with the four drive  
>> bays devoted to providing NFS (stripe accros mirrors; (tested)  
>> spare drive in a desk drawer. What's different is that I planned  
>> the system this way: I installed CentOS from a DVD with none of the  
>> disk drives installed, just the USB, and CentOS had no choice but  
>> to install on the USB.
>
> I was in the process of building a usb stick from scratch this way,  
> when I read your posting. I was heartened to know that in the right  
> circumstances, it works. In my case, I didn't expect any joy, as  
> this is the method I used to build the SATA disk that kernel panics  
> booted off the usb bus. The install doesn't know whether it's  
> writing to a usb stick or to a SATA drive, so I couldn't see how the  
> files on the different types of devices would be any different. As  
> it turns out, the usb stick I made this way kernel panics too.
>
> The install makes an optional syslinux boot usb stick (which can  
> boot your main install, in my case on a usb stick, if you choose not  
> to install the standard boot loader on your installed disk). So I  
> had two ways of booting the usb stick. The syslinux boot kernel  
> panics too.
>
>> It boots fine. When I added the disk drives later, they were  
>> recognized, and I could configure them as I intended.
>
> I'm happy for you.
>
>> As to performance, once the OS gets loaded from USB, just about the  
>> only access to the USB is to write log files.  There's plenty of  
>> RAM to cache the OS file system, and to cache writes while they're  
>> waiting to get written.  In my setup, the rate of writes to the USB  
>> is far less than its bandwidth, so I'm having no performance  
>> trouble there.
>
> I'm glad to hear performance isn't a problem. I don't care about  
> performance. Current usb sticks are fast enough and the files are  
> only going to be read once and sit in cache (32G RAM) after that.
>
> This morning it occured to me that the difference in booting off a  
> usb stick and a SATA drive is that I'm using the distribution's  
> generic kernel, which likely won't have the usb drivers in it, but  
> will load the usb drivers as modules later. (I used to make custom  
> kernels with just the right drivers built into the kernel, but I  
> gave up on this a while ago. Now I want installs that boot anywhere  
> I put them.)
>
> So I made the generic initrd (which I've never needed to use), using  
> the supplied script, and this time the kernel stops with
>
> can't mount /dev/sda1 on /mnt
>
> and drops me into a shell. This is a step forward.
>
> looking with ls, there are no /dev/sd*  in /dev
>
> I'm now going to mess around around with initrd files and as well  
> build a kernel with all the usb drivers built in.
>
> If anyone knows the solution to the current situation I'd be glad to  
> hear about it.
>
> Thanks Joe
>
> -- 
> Joseph Mack NA3T EME(B,D), FM05lw North Carolina
> jmack (at) wm7d (dot) net - azimuthal equidistant
> map generator at http://www.wm7d.net/azproj.shtml
> Homepage http://www.austintek.com/ It's GNU/Linux!
> -- 
> This message was sent to: Roger <rogerb at bronord.com>
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