20.04 Lack of space on Root

[Holger_Gehrke]

The EFI System Partition is important for the boot process. If you're using UEFI for booting then that partition should be marked 'esp, boot' in the output of 'sudo parted -l'. It should also be mounted as /boot/efi. UEFI is capable of reading extensions from files in a FAT filesystem. At least part of GRUB is installed that way on UEFI-systems. Unless you're running in BIOS-compatible mode (sometimes called CSM - compatibility support module - or Legacy Mode) removing the ESP would make it impossible to boot from that disk.

As I already said I'm surprised to see an ESP inside an extended partition. Normally you'd use GPT with UEFI which can have more than 4 partitions thereby making the stupid 'extended partition'-hack unnecessary.

Holger

[Robbyx]

The EFI System Partition is important for the boot process. If you're using UEFI for booting then that partition should be marked 'esp, boot' in the output of 'sudo parted -l'. It should also be mounted as /boot/efi. UEFI is capable of reading extensions from files in a FAT filesystem. At least part of GRUB is installed that way on UEFI-systems. Unless you're running in BIOS-compatible mode (sometimes called CSM - compatibility support module - or Legacy Mode) removing the ESP would make it impossible to boot from that disk.

As I already said I'm surprised to see an ESP inside an extended partition. Normally you'd use GPT with UEFI which can have more than 4 partitions thereby making the stupid 'extended partition'-hack unnecessary.

Holger

Thank you for your reply. Of the drives on the system, this is the one that should show the EFI partition using sudo parted -lparted -l. This seems to mean that the EFI is redundant and can be deleted. I have found that compatibility mode is enabled. I will therefore remove the efi partition. As for GPT, can I install it only on the root drive, I think I have to do the whole drive. It will be very messy and difficult to do this if the whole drive needs reformatting.

Model: Force MP510 (nvme)
Disk /dev/nvme0n1: 960GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags: 

Number  Start   End     Size    Type      File system  Flags
 1      1049kB  56.0GB  56.0GB  primary   btrfs        boot
 2      56.0GB  110GB   54.0GB  primary   btrfs
 3      110GB   112GB   2000MB  extended
 5      112GB   112GB   182MB   logical   fat32
 4      270GB   960GB   690GB   primary   btrfs

[CelticWarrior]

GPT isn't something you install: https://en.wikipedia.org/wiki/GUID_Partition_Table

And no, the EFI partition is NOT redundant. Unless you previously install Grub for MBR ("msdos") it won't boot in Legacy mode. And such attempt for no good reason is dumb. Maybe what you should do instead, the smart thing, is delete everything by creating a new GPT partition table and reinstall using proper partition sizes according to your specific needs.

[Robbyx]

GPT isn't something you install: https://en.wikipedia.org/wiki/GUID_Partition_Table

And no, the EFI partition is NOT redundant. Unless you previously install Grub for MBR ("msdos") it won't boot in Legacy mode. And such attempt for no good reason is dumb. Maybe what you should do instead, the smart thing, is delete everything by creating a new GPT partition table and reinstall using proper partition sizes according to your specific needs.

I am now unclear about the way forward. Perhaps the right path can be resolved with additional information:

I am not running a dual machine. I do not have windows installed in it.

I have often reinstalled the root partition via a reformat, because of upgrades to Ubuntu. I have not done anything out of the ordinary when upgrading. I know that my system uses a linux grub. My fstab uses UUIDs; does this imply that I have GPT installed and is being used currently?

Is it possible to move the EFI partition to a new location on the same drive, via a live CD? If so do I have good grounds to assume that the system will boot with the EFI in the new location?


Are there any tests I can run to show how the drive is booting currently?

With the root drive currently sized at 52gb including unused space of 21gb, I am no longer getting the low space report. Is 21gb a sufficiently large free space for the BTRFS file system to use without running out of space?

[tea for one]

Are there any tests I can run to show how the drive is booting currently?

You can check the boot mode via the terminal:-

[ -d /sys/firmware/efi ] && echo "UEFI mode" || echo "Legacy mode"

[Robbyx]

You can check the boot mode via the terminal:-

[ -d /sys/firmware/efi ] && echo "UEFI mode" || echo "Legacy mode"

The check shows legacy mode. How far does this result permit me to remove the extended partition with the EFI sub partition in it? Assuming this is the green light to remove the extended partition, can I simply back up the EFI partition to another drive and restore it to a new location outside of the extended partition if I cannot reboot without it?

[jay-eich]

Hey there,
Try sudo du / | more
without the limit of one deep. Relax. Be nosy.

I found a lot in /root/.cache for the mesa shaders. (I have an AMD/ATI GPU.)

In the 'Apt' section, I also use the 'AutoRemove' option to get rid of unused packages.

Also, check what languages are white-listed under locale. If you select 'Localizations' under 'System', that xcan clean up a lot...

Here is my summary for comparison (Ubunto Mate 20.4.1)
sudo du -hs /etc /lib /lib32 /root /sbin /sys /usr /var
13M /etc
0 /lib
0 /lib32
68K /root
0 /sbin
0 /sys
6.9G /usr
2.7G /var


Hope that helps...
Jay

[Robbyx]

sudo du -hs /etc /lib /lib32 /root /sbin /sys /usr /var
22M	/etc
4.0K	/lib
4.0K	/lib32
700K	/root
4.0K	/sbin
0	/sys
7.5G	/usr
5.9G	/var

Jay:
I would suggest the only that needs more insight for space recovery is the /var size, as compared to your system.

[Robbyx]

I have just deleted the EFI partition and successfully restarted Ubuntu. I have also removed the parition that contained the EFI partition so now that space is unallocated.

The order of my HD is now root,home,unallocated, data.

When I used gparted to set up moving the home to the right of the unallocated space, there was a warning. Gp warned that I was also going to move the start sector and that could prevent the system from booting. Assuming that the start sector is only in the first partion ie the root, can I safely ignore the warning as I am not proposing to move the root partition?

Have I misunderstood where the start sector is to be found?

[Robbyx]

This does seem to be a baffling question at the moment, nevertheless there must be a clue somewhere?

Which version and flavour of Ubuntu are you using?
What are you trying to do when the low space message appears?
I'm not familiar with bleachbit, is it a reliable utility?
Possibly, the file manager is reporting incorrectly due to an unknown reason?

Can you post the output from:-

df -t btrfs

I have found the cause. I had set up the timeshift backup program to use BTRFS. Unfortunately, it can only backup btrfs drives when it uses the system partition to save the snapshots. Without cutting back drastically on them, the system's spare space quickly filled.

I have deleted the backups and changed the method of backup to rysnc. I have also changed the snapshot location to a different drive, so there is also a better chance of recovery if the main drive goes down.