When metadata only copy up feature is enabled, overlayfs will only copy up metadata (as opposed to whole file), when a metadata specific operation like chown/chmod is performed. Full file will be copied up later when file is opened for WRITE operation.
In other words, this is delayed data copy up operation and data is copied up when there is a need to actually modify data.
There are multiple ways to enable/disable this feature.
[…]
Need to review each of these kernel boot parameters if these are still required.
boot=live
plainroot
union=overlay
ip=frommedia
noeject
nopersistence
boot=live
Activates live boot (package by Debian). Probably OK.
plainroot
See file /lib/live/boot/9990-main.sh for variable PLAIN_ROOT. Takes a different code path. Not sure.
union=overlay
union=overlay|aufs
By default, live-boot uses overlay. With this parameter, you can switch to aufs.
Seems default anyhow. Could therefore be removed but never mind.
ip=frommedia
Seems required to not write /etc/network/interfaces, ok.
noeject
Do not prompt to eject the live medium.
This option causes live-boot to reboot without attempting to eject the media and without asking the user to remove the boot media.
Do we want this? Why?
When shutting down Whonix-Host ISO it seems to not poweroff but say “please remove ISO” or something which is bad (in case users want to quickly shutdown to clear RAM).
nopersistence
disables the “persistence” feature, useful if the bootloader (like syslinux) has been installed with persistence enabled.
Not sure yet. Probably ok for now. Looks related to selective persistence.
union=overlay Yes to keep it, probably redundant, but you never know when the default changes
ip=frommedia Yes, " Seems required to not write /etc/network/interfaces , ok."
noeject Yes, let’s keep it, maybe better for quick shutdown.
nopersistence, Seems we could remove this one. Maybe persistence (like Tails) could be a nice feature in the future for Whonix-Host
Btw I have just noticed that default Whonix-Host ISO (Isolinux, didn’t check on GRUB yet) does not have these kernel parameters. Is this on purpose? Or should we harmonize it and have the same exact parameters for VMs and Whonix-Host live-mode?
Edit by Patrick:
added bullet points for easier readability
Not on purpose. I guess that happened because these boot options are only set when booting for example Whonix-Workstation VM into Live Mode. Therefore overlooked.
Yes, that would be good.
Kernel command line persistent mode changes from ⚓ T950 set kernel.printk sysctl to prevent kernel info leaks were not added yet. But not sure we should add them yet. It’s not time to lower verbosity for Whonix-Host boot yet.
Perhaps rather the opposite. Add more verbosity?
Btw installing package debug-misc on Whonix-Host ISO wouldn’t increase debugging because current implementation ignores that raw image’s /boot/grub/grub.cfg (which is created from /etc/default/grub.d, i.e. /etc/default/grub.d is ignored) (for now hardcoded).
Could use a script to sanity check if kernel boot parameters are sync (no differences for Whonix-Host ISO) but not easy.
Why are kernel boot paramaters (such as spectre_v2=on spec_store_bypass_disable=on tsx=off …) defined in both files:
Could you please create tickets (separate forum topics) for anything that isn’t easy to resolve? [Don’t worry the forum tags too much. I can do these later.]
“I thought it was the VirtualBox’s vdi hard disk drive that was full, but it was much easier. Just a “df -h” and I realized that my host disk was full!”
My disk has enough free space. When I used VB 6.1.18 with LisLogic SAS live mode on the host worked well and I was able to start whonix VB with a live mode on the host. But now when live mode is on on the host I got this error - VERR_DISK_FULL
Also now is impossible to switch AHCI VB to read only.
