On Fri, 16 Mar 2018 12:45:09 +0100, Newdo  wrote:

> Hi,
>
> the final goal of my current efforts is to have a readonly filesystem
> without superfluous write access to the internal sd card.
>
> Currently i am using berryboot and find accesses tp mmcblk0p2 by jdb2
> when monitoring the disk activity with iotop.
>
> Looks as if this is caused by the journaling of ext4 filesystems?
>
> The mmcblk0p2 seems to be managed by berryboot, found no option to make
> is r/o at startup.
>
> I have an USB stick attached for storing acquired data during normal
> 24/7 operation.
>
> Would be enough space for moving the os to the USB device.
>
> Q1: How can the access be suppressed / How to make the sd card r/o

There is no need to make the SDcard read-only if only the /boot FAT
partition is there.
Once the operating system is located on the USB stick, it will only
access USB storage.

/boot/cmdline.txt tells the bootloader where the OS is located.

This could get you started:

https://www.raspberrypi.org/forums/viewtopic.php?f=66&t=12015&start=50
https://www.makeuseof.com/tag/how-to-turn-your-raspberry-pi-into-an-always-on-d
ownloading-megalith/
https://zeroset.wordpress.com/2012/10/03/move-an-existing-raspbian-installation
-from-memory-sd-card-to-usb-flash-drive-stick/
http://www.paragon-drivers.com/extfs-windows/


There are several other reasonable tutorials on the web, some old, some
new. I boot from a USB harddrive, using the SD card as bootstrap (only
/boot), combining info from several tutorials/forums/blogs, without
berryboot.


> Q2: How can one of the current boot images exported using the  berryboot
> menu (.img192 file) be brought to a fresh sdcard without using
> berryboot? (in order to use the known hints about making a readonly
> filesystem)

I don't know the answer to that, but you can always copy partitions with
the dd utility.


https://www.berryterminal.com/doku.php/berryboot
mentions booting from USB, they might have more info as well.
--
Regards,
Kees Nuyt

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