Error when booting: Diskfilter writes not supported

[whateverthing]

Hi -- I installed LL4.0 a few days ago, onto the same old laptop I was using with LL3.8 before. Now when I boot, I see an error screen that says:
"Error: diskfilter writes are not supported.
Press any key to continue..."

I've done some Googling, and it apparently comes from GRUB. It seems to have something to do with drive partitions? I definitely don't understand the problem or the answer.
https://askubuntu.com/questions/468466/d...281#498281

It would be nice to get rid of the error. Any help would be appreciated! Should the installation process have made different partitioning choices?

[kpanic]

Hi,

Since you installed 4.0 just a few days ago, you probably don't have much important data in there yet?
If you have, can you store it temporarely to a USB stick for example?
This is because I suggest that you make a fresh new installation of LL 4.0.

When you begin the new installation, don't start the actual installation yet, just let the live OS be in the RAM
and open a terminal. In the terminal, use gdisk to repartition your HD. If you have just one HD and LL will be
the only OS in it, then just create two partitions with gdisk:

NOTE: If you make a mistake/typo in any of the following, you may always
          press CTRL+C and start again.

Code:

sudo su

Code:

gdisk /dev/sda

Now, make sure you have all of your important data backed up somewhere, in an USB stick
or external HD or such, since the data will be lost from your HD when you repartition it!

Next you see:

Code:

Command (? for help):

Press key 'o' (and ENTER), to create a new empty GPT partition table.

Finally create two new partitions: /dev/sda1 and /dev/sda2.

Press key 'n' to create a new partition.

Code:

Command (? for help): n

Now, the first partition will be your root partition, so create it
almost as big as the disk is, but leave at least 16777216 sectors unallocated for swap.
And create the second partition (for swap) the same way you created the first one:

Press key 'n' to create a new partition.

Code:

Command (? for help): n

Now you may allocate the rest of the disk for swap and accept the
defaults by pressing ENTER a few times.

This is a little detail but it makes sense to change the swap partition's ( /dev/sda2 )
type, so command:

Code:

Command (? for help): t
          Partition number (1-2): 2
          Hex code or GUID (L to show codes, Enter = 8300): 8200

(And why not change the root partition's type also (if you use 64bit kernel).

Code:

Command (? for help): t
          Partition number (1-2): 1
          Hex code or GUID (L to show codes, Enter = 8300): 8304

Let's also toggle the root partition's legacy boot attribute:

Code:

Command (? for help): x
Expert command (? for help): a
          Partition number (1-2): 1
          Toggle which attribute field (0-63, 64 or <Enter> to exit): 2

If you got the message: "Have disabled the 'legacy BIOS bootable' attribute",
then toggle again, by pressing '2' again.

Finally write the new partition table to disk by pressing 'w'

Code:

Command (? for help): w

Ignore the warnings.

Now you are ready to create the filesystem and swap.
Command:

Code:

partprobe /dev/sda

Then:

Code:

mkfs.ext4 -t ext4 -m 3 -L root /dev/sda1

Then:

Code:

tune2fs -c 10 -e remount-ro /dev/sda1

Then initialize the swap partition:

Code:

mkswap -L swap /dev/sda2

Now you can exit the terminal and click the Install button.
When the installer comes to the partitioning, just edit the 2 entries
and DO NOT choose the 'format' option', since you already did it.
Just mount /dev/sda1 to /
and choose /dev/sda2 to be the swap partition.

Then just finish the installation.

I prefer to do this partitioning before the actual installation, since
you can fine-tune every little detail for the filesystem(s), which is
usually not possible to do when the graphical installer lets you do it.

And it may save you from a lot of time/harm, what some hardware unfortunately
may cause.

Please ask if I may be of any help?

Have fun

[whateverthing]

Wow [member=7701]kpanic[/member] thank you for the detailed instructions! I could pretty easily re-install, so I'll give this a try.

[whateverthing]

Well, I got to the step where I create the first partition, and am not sure what option to choose here:

Code:

Warning! Main partition table overlaps the first partition by 34 blocks!
You will need to delete this partition or resize it in another utility.

Command (? for help): o
This option deletes all partitions and creates a new protective MBR.
Proceed? (Y/N): y

Command (? for help): n
Partition number (1-128, default 1):
First sector (34-30548014, default = 2048) or {+-}size{KMGTP}: 

Should I take the default value?

Also, is that warning a problem?

[kpanic]

Well, I got to the step where I create the first partition, and am not sure what option to choose here:

Code:

Warning! Main partition table overlaps the first partition by 34 blocks!
You will need to delete this partition or resize it in another utility.

Command (? for help): o
This option deletes all partitions and creates a new protective MBR.
Proceed? (Y/N): y

Command (? for help): n
Partition number (1-128, default 1):
First sector (34-30548014, default = 2048) or {+-}size{KMGTP}: 

Should I take the default value?

Also, is that warning a problem?

Hi,

That warning is quite common and you may ignore it since you are creating a new partition table anyway

- kpanic

[kpanic]

...and yes, you can choose the default value, which is 2048.

Can you tell me how many sectors there are ( gdisk tells this when you start it ) on your hard drive?

[kpanic]

...and yes, you can choose the default value, which is 2048.

Can you tell me how many sectors there are ( gdisk tells this when you start it ) on your hard drive?

Sorry, my mistake. When you launch 'gdisk /dev/sda', you need to press 'p' and ENTER to get
the amount of sectors in the hard drive / ssd.

[whateverthing]

[member=7701]kpanic[/member] ... It reports End sector 312580095, Size 149.0 GiB.

But I'm seeing all the discussion about swap partition, that Ubuntu 18.04 uses a swap file instead. So is there a different partition plan we should consider? What about a boot partition? I don't have a good understanding partition planning, and I see many options recommended, like this (which also suggests using a swap partition):
https://www.linuxtechi.com/ubuntu-18-04-...reenshots/

And this discussion says the OS will use a swap partition if it finds one:
https://ubuntuforums.org/showthread.php?t=2390779

But is a swap file a more efficient use of drive space, since it can vary in size as needed? I don't really know the issue, I'm just guessing.

Thanks for continuing to help with advice here!

[kpanic]

[member=5059]whateverthing[/member], that's the power of Linux, things can be done in many ways. Sometimes though, this power may cause
some confusion. The reason why I prefer a swap partition instead of a swap file is, that if the Linux begins to swap, it always
makes the computer a bit ( or more ) slower. When you use a swap file, then the ext4 file system driver must do extra work
since the swap file is in the ext4 formatted partition and so it makes things even slower compared to, if you use a swap
partition, which is not formatted as ext4.

The file system driver is one of the most important parts of the Linux kernel and ext4 is very sophisticated file system and
requires a decent amount of resources from the CPU too - which is not the case with swap partition, which is much easier
for the kernel to maintain. So, it's faster and - as a bonus - it does not fragment the file system at all.

You may create many partitions, including the /boot partition but you don't need a separate /boot  partition. The boot loader
can load the kernel from the root ( / ) partition as well.

Since your HD seems to be about 149 Gb, I recommend that you create a 145Gb root partition and 4Gb swap should be enough. Here is how to do it:

First boot the installation media.

Then make sure, that LL will not auto-mount your new partitions:
Go: 'Menu' -> 'Settings' -> 'Removable Drives and Media'
And under "Removable Storage" make sure that every button is unchecked
and then close the settings.

Then open the terminal, become root and run gdisk:

Code:

sudo su

  (This should be done, so that you won't need to type 'sudo' all the time...)

Code:

gdisk /dev/sda

Create empty partition table

Code:

Command (? for help): o

Create the root partition

Code:

Command (? for help): n

Accept the default partition number 1 and the default first sector 2048 by
pressing ENTER two times.

Then it asks the last sector, type '+145G' and press ENTER

Code:

Last sector (2048-312580095, default = 312580095) or {+-}size{KMGTP}: +145G

Then it asks the partitions type code, choose 8304 and press ENTER

Code:

Hex code or GUID (L to show codes, Enter = 8300): 8304

Then create swap (the second partition)

Code:

Command (? for help): n

Then it asks again the first sector and the size. This time you may choose
the defaults by pressing ENTER three times until it asks again the partitions
type code. Choose 8200 and press ENTER.

Code:

Hex code or GUID (L to show codes, Enter = 8300): 8200

Then toggle the legacy boot flag. Press 'x'

Code:

Command (? for help): x

Then 'a'

Code:

Expert command (? for help): a

Then '1'

Code:

Partition number (1-2): 1

Then '2' followed by two ENTERs

Code:

Toggle which attribute field (0-63, 64 or <Enter> to exit): 2

Now you can check how your partition layout looks like, press 'p'

Code:

Expert command (? for help): p

You should see the two partitions.
Finally write the new layout to disk, by pressing 'w' and ENTER.

Code:

Expert command (? for help): w

(Ignore the warning)

Then make sure the kernel sees the new layout by commanding

Code:

partprobe /dev/sda

Then create the ext4 filesystem

Code:

mkfs.ext4 -t ext4 -m 2 -L root /dev/sda1

(Sometimes it takes some time, so please don't interrupt...)

Then create the swap

Code:

mkswap -L swap /dev/sda2

Then some fine-tuning

Code:

tune2fs -c 10 -e remount-ro -O ^dir_nlink,^huge_file /dev/sda1

Now you are ready and may exit the terminal and begin the installation.
And again, when the installer comes to the partitioning, just edit the two partition
entries. Set the /dev/sda1 partition to be ext4 and mount it to /

And set the /dev/sda2 to be the swap partition.

Do NOT check the 'format' option, since it's done already.
Then just finish the installation.

And finally as I said. Things can be done in many different ways. You may ignore these instructions
if you don't feel comfortable using the terminal - then the graphical installer does everything for you.
However, with the graphical installer you are not able to be so precise.

I hope this helps

[whateverthing]

I got a ways through it, but it failed at the mkfs command:

Code:

linux  ~  sudo partprobe /dev/sda
linux  ~  sudo mkfs.ext4 -t ext4 -m 2 -L root /dev/sda1
mke2fs 1.44.1 (24-Mar-2018)
/dev/sda1 contains a LVM2_member file system
Proceed anyway? (y,N) y
/dev/sda1 is apparently in use by the system; will not make a filesystem here!
linux  ~ 