On 07/11/2019 15:44, RobH wrote:
> On 07/11/2019 00:56, Vince Coen wrote:
>> Hello Chris!
>>
>> Thursday November 07 2019 13:10, you wrote to RobH:
>>
>>   > On 07/11/2019 12:52, RobH wrote:
>>   >> I'm having a hard time finding the information I want , so I ask
>>   >> here:
>>   >>
>>   >> Has anyone had success using an external disk with the pi 4, and
>>   >> preferably booting from it.
>>   >>
>>   >> The other option I thought about was to put some other version of
>>   >> Linux on it, ubuntu?, but using etcher in linux doesn't do it, as
>>   >> it's an iso.
>>   >>
>>   >> Thanks
>>
>>   > Not a Pi4 but I have Pi3+s booting from SD card (holding only the
>>   > /boot partition) and 128/256Gb SSD (mSATA in mSATA to USB3
>> adapter) as
>>   > root. Quite easy if you follow the instructions. I never had much
>> luck
>>   > booting directly from the USB SSD, hence the above arrangement.
>>
>>   > --
>>   > Chris Elvidge, England
>>
>>
>> I use a 3B+ sitting in a x830 box and card with a 1TB dasd  .
>> The drive has the Rasbian installed and it powers up, boots to the the
>> USB
>> drive.
>>
>> Every thing works - so far but I do not run it daily just as a when as
>> I use a
>> server system for day to day
>> development and other activities such as BBS, FTP, SQL, Apache, IBM
>> m/f server
>> or services.
>> This hold a lot of dasd unit giving over 10+ TB storage all in 16GB
>> Ram with a
>> modular PSU so it is light on
>> power needs but a Pi is a heck of a lot less :)
>>
>> Did want to get a Pi4 but will not fit into the current X830 case so
>> will wait
>> until a revised X830 combo
>> comes out.
>>
>>
>>
>> Vince
>>
> Thnks, and are there any simple instructions for doing that for a simple
> lad like me.

Install Raspbian (other OSs are available) onto SD card as usual. Update
as necessary.
Format external drive. Include a swap partition, root partition plus any
extra ones required.

Make a note of UUID/PARTUUID of the new root (and swap if used)
partition. (see "man blkid"). Mount the new root partition on (say) /mnt
and then
rsync -avx / /mnt to get the OS onto the usb drive.

You now need to change the cmdline.txt file on the SD card boot
partition to add to the root= parameter. Make a copy before you edit
this file. Should look something like this:

dwc_otg.lpm_enable=0 console=serial0,115200 console=tty1
root=PARTUUID=5cf6b9c2-9894-cd47-933e-ad3840ae4e5c rootfstype=btrfs
elevator=deadline fsck.repair=yes rootwait quiet splash
plymouth.ignore-serial-consoles net.ifnames=0 biosdevname=0
usbhid.mousepoll=0

Note the PARTUUID is the one you remember from your note above. (You can
use the UUID instead, though; root=UUID=uuidfromabove). net.ifnames=0
and biosdevname=0 makes the ethernet and wireless ports revert to eth0
and wlan0. usbhid.mousepoll=0 compensates for a USB mouse on my system.
Commands in cmdline.txt must be all one line, and only on one line.
Remove any blank lines in the file.

Now edit /etc/fstab on the NEW root partition (/mnt/).
If there is an entry for /dev/mmcblk0p2 on /, change the /dev/mmcblk0p2
to UUID=theuuidfromabove. If not OK, it'll find it from the cmdline.txt
file.
Put a new entry:
/dev/mmcbl0p2 /mnt/oldroot ext4 noauto,defaults 0 0
(and remember to make directory /mnt/oldroot AFTER unmounting the new
root partition). This will stop your old root being mounted at boot.
(You can still mount it with mounr /mnt/oldroot, if necessary.)

Add an entry for swap if using a partition.

umount /mnt; mkdir /mnt/oldroot

Reboot and keep your fingers crossed.

I don't think I've left anything out!!

If it fails, take out the SD card and revert the cmdline.txt file in
another computer. It's on a vfat partition so a Windows PC can read it, too.
Put it back and reboot. Check all the above. If it still fails, note the
errors and come back.

Good luck

--

Chris Elvidge, England

--- SoupGate-Win32 v1.05