Error during copy: Read-only file system (os error 30)

I can certainly reproduce the following error now on one of my systems on "bare metal", which seems weird because it should not happen.

I run following command: disko-install --flake 'github:Zocker1999NET/server/gaming-setup-steamos#steamos.pc.6nw.de' --disk main /dev/sda --mode format (IMO the config should be irrelevant for this issue, but just in case)

Every time I executed this for the last 4 times, disko-install succeeds to build the config, then starts to partition the device, then starts the manual transfer of the /nix/store, and then fails to complete because (last log lines):

+ device=/dev/sda
+ efiGptPartitionFirst=1
+ type=gpt
+ device=/dev/disk/by-partlabel/disk-main-root
+ extraArgs=()
+ declare -a extraArgs
+ format=ext4
+ mountOptions=('defaults')
+ declare -a mountOptions
+ mountpoint=/
+ type=filesystem
+ findmnt /dev/disk/by-partlabel/disk-main-root /mnt/disko-install-root/
+ mount /dev/disk/by-partlabel/disk-main-root /mnt/disko-install-root/ -t ext4 -o defaults -o X-mount.mkdir
+ destroy=1
+ device=/dev/sda
+ imageName=main
+ imageSize=2G
+ name=main
+ type=disk
+ device=/dev/sda
+ efiGptPartitionFirst=1
+ type=gpt
+ device=/dev/disk/by-partlabel/disk-main-ESP
+ extraArgs=()
+ declare -a extraArgs
+ format=vfat
+ mountOptions=('defaults')
+ declare -a mountOptions
+ mountpoint=/boot
+ type=filesystem
+ findmnt /dev/disk/by-partlabel/disk-main-ESP /mnt/disko-install-root/boot
+ mount /dev/disk/by-partlabel/disk-main-ESP /mnt/disko-install-root/boot -t vfat -o defaults -o X-mount.mkdir
+ rm -rf /tmp/tmp.5HpXTbdhe2
Copying store paths
[################################################################################################################>---------------------------------------------------]    2.66 GiB / 3.87 GiB    |  69% |  35.01 MiB/s  | 00:00:35 remaining00:37:52 [ERROR] Received error: Error during copy: Read-only file system (os error 30)
00:37:52 [ERROR] Error copying: "/nix/store/hscvhz3bg5yzagpj2hgxi8y4f4zqz4ny-nix-2.31.2-man/share/man/man1/nix-env-uninstall.1.gz" -> "/mnt/disko-install-root/nix/store/hscvhz3bg5yzagpj2hgxi8y4f4zqz4ny-nix-2.31.2-man/share/man/man1/nix-env-uninstall.1.gz"; aborting.
00:37:52 [ERROR] Error copying: "/nix/store/hscvhz3bg5yzagpj2hgxi8y4f4zqz4ny-nix-2.31.2-man/share/man/man1/nix3-store-repair.1.gz" -> "/mnt/disko-install-root/nix/store/hscvhz3bg5yzagpj2hgxi8y4f4zqz4ny-nix-2.31.2-man/share/man/man1/nix3-store-repair.1.gz"; aborting.
00:37:52 [ERROR] Error copying: "/nix/store/hscvhz3bg5yzagpj2hgxi8y4f4zqz4ny-nix-2.31.2-man/share/man/man1/nix3-derivation-show.1.gz" -> "/mnt/disko-install-root/nix/store/hscvhz3bg5yzagpj2hgxi8y4f4zqz4ny-nix-2.31.2-man/share/man/man1/nix3-derivation-show.1.gz"; aborting.
Error: Error during copy: Read-only file system (os error 30)
00:37:52 [ERROR] Error copying: "/nix/store/hscvhz3bg5yzagpj2hgxi8y4f4zqz4ny-nix-2.31.2-man/share/man/man1/nix3-flake-init.1.gz" -> "/mnt/disko-install-root/nix/store/hscvhz3bg5yzagpj2hgxi8y4f4zqz4ny-nix-2.31.2-man/share/man/man1/nix3-flake-init.1.gz"; aborting.
Loading nix database
installing the boot loader...
chroot: failed to run command ‘/nix/var/nix/profiles/system/activate’: No such file or directory
chroot: failed to run command ‘/nix/var/nix/profiles/system/sw/bin/bash’: No such file or directory
disko-install failed

I am very certain that the drive I’m using is good for two reasons: a) I do not run into problems when running e.g. pv /dev/zero > /dev/sda. b) The kernel (dmesg) does log no error whatsover while disko-install fails.

And, to add, I can also reproduce this issue in a NixOS test of my subproject disko-install-menu, more certain in the installDefault test. While there the issue only occurs roughly every 2nd or 3rd run, the issue occurs on 3 completely different systems I am able to run this test on.
For a long time, I thought this issue is limited to a quirky misbehavior of qemu/KVM/…, but now that I see this issue with "real" hardware, I do no longer think that this is the case here.

And also, as well as on "real" hardware & when running as a NixOS test, the installation does not always fail at the same files, but always in a similar ballpark of gibibytes transferred.

I have no idea how to further debug this, therefore I decided to report this here.

Reproduce the failure with the documented disko-install command and the disko-install-menu tests/installDefault.nix test. Start by tracing the manual /nix/store copy after the root and boot filesystems are mounted, using the reported destination and failing paths. Done means identifying why the destination becomes read-only and making installation complete reliably across repeated runs.