Unable to remount partition as read only
 

I am trying to remount partition as read only on Xubuntu from grub recovery console. The partition is mounted like this: I am using this command to remount it as read only: But when i check the mount points it still shows that the partition is still mounted as rw (read,write).

Why it doesn't want to remount it as read only?

You (as a user) can't remount the root as ro. Simple as that. Lots of reasons, but /var/logs is one that most can implicitly understand.

where exactly are you when you try that?
i don't think it's the grub console.
have you booted into recovery mode (text only, root prompt)?

I should have said that i am trying this on Xubuntu virtual machine. I am trying to compact the .vdi disk but first i have to remount sda1 as read only and then run zerofree.

As an alternative, boot the VM from a SystemRescueCD ISO and run zerofree from that.

See here: https://snippets.khromov.se/shrinkin...with-zerofree/

The link also uses an alternative runlevel 1 method which may prove useful if you don't want to boot from a separate ISO.

Thanks, i used SystemRescueCD.

>"You (as a user)..." [booted 'single', via grub menu choice of "recovery console"]
freaked me out momentarily, thinking 'user' meant NON-root, but it meant 'person vs boot_code'
>"/var/logs is [reason]" means: files in /var/log are 'open': try/see: fuser /

>OP: "...compact the .vdi [via] zerofree" Oh! COOL! I've wondered HowTo do this! web-search-words:
HOWTO: shrink|"Reduce the size of" a dynamic VDI file in VirtualBox