On 07/11/2019 16:36, Chris Elvidge wrote:
> 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
>

I've made a root partition, as  well as a swap partition on a spinning
160Gb disk.

This is my present cmdline.txt file before any changes, and it looks a
bit different than new or changed line. Does it matter.

dwc_otg.lpm_enable=0 console=serial0,115200 console=tty1
root=PARTUUID=4eae5394-02 rootfstype=ext4 elevator=deadline
fsck.repair=yes rootwait quiet splash plymouth.ignore-serial-consoles

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