Arch Linux

jussih

Member

From: Finland

Registered: 2017-10-24

Posts: 12

How do the cow (copy on write) options work in Arch / Archiso ?

Background story:
I have a USB stick with 2 partitions. One FAT and one ext4. I want to install a custom Archiso build to the FAT partition, and have the second ext4 partition as a persistent CoW partition for the ISO. I give the bootloader the boot parameters

cow_device=/dev/disk/by-uuid/<COW_PART_UUID> cow_persistent=P

Problem:
During bootup, the persistent-meant ext4 partition is mounted, but it seems to be mounted to

/run/archiso/persistent.../

And if I try to create a test file into the user home directory, it will be lost after a reboot. So it will not create the copy on write file to the /run/archiso/...

Questions:
How could I make it so every WRITE to this root partition would actyally do a copy on write file to the ext4 partition I have done for this use? Or is this impossible to achieve?

Why does it just do some random folder to /run/archiso/persistent/ , does the persistent feature assume that I would write all necessary files into that folder?

Last edited by jussih (2018-09-28 13:15:35)