Subiquity only provisions half of available space for root logical volume

This is by design. There's not much point in using LVM if you then completely fill up the volume group with a single logical volume -- you can't take snapshots, for example -- and expanding a LV later is much easier than shrinking one.

> There's not much point in using LVM if you then completely fill up the volume group with a single logical volume

That's not true. LVM is necessary for LUKS encryption, which is why I am using it. I want a single encrypted volume which uses the entire space.

That's by design? So you think it's better to ignore what the user asked for because you know what we want better than we do? That's so Microsoft of you.

The result is you're making subiquity less dependable (will I get what I ask for or not?) and less useful so that we have to work around it. Thanks for the extra work ... and yes I'm upset about the software taking a task that should be simple and making it harder.

Please reconsider this. This action it's doing now is a bug! If you want to keep that action, at least add a flag (e.g. --useall) or something to allow those of us who have reasons to do this to get what we need.

I just created Ubuntu 20 virtual machine and allocated disk space from service provider.
Only to notice that half of disk space was used.
This is a mine, if you dont know this non logical odd default behaviour you are paying disk space you cannot use.
Please change this.
This should be other way around. If someone does not want to use full space to be used he/she surely will know what to do. I use LVM bc its easy add extra disks to it later and because its default installation option.

There are some decisions that are smart. This decision was not one of those.

I was setting up multiple machines and the default is now to use half a disk, which means I now need to manually edit every single partition configuration on each of those machines instead of using the default full disk like every other Linux distribution in the world does when it asks "USE FULL DISK?".

I've been Ubuntu's biggest fan since the early days, but ill-conceived decisions like this are the reason trust gets eroded and users move on to other distributions, especially since this wasn't even documented anywhere. This essentially wasted 5 hours of my time to fix your decision.

@mwhudson

> This is by design.
> There's not much point in using LVM
> if you then completely fill up the volume group
> with a single logical volume

Great. Then change the wording on the install CLI screen from "Use the full disk." to say "Use half the disk because there's not much point in using LVM if you then completely fill up the volume group with a single logical volume."

> -- you can't take snapshots, for example

Hi I'm a new Linux user installing this for the first time. I don't know what this means and I'll bet I will care MUCH more about having only half my disk space available than I will about my ability to do whatever this is.

> -- and expanding a LV later is much easier than shrinking one.

Great, then put how to do this in the install text, or maybe even the documentation.

In fact there is no mention of any of this LVM or "half disk" stuff at all in the official documentation:
https://ubuntu.com/tutorials/install-ubuntu-server#10-confirm-partitions

And yes I know "it's open source fix it yourself" which is fine around the edges of Ubuntu - but this is literally the FIFTH keystroke in the million-keystoke journey that is learning about the linux server world. NO ONE new will NOT be at least slightly affected by this.

I signed up here just to post that I agree with the others here. This is unexpected behavior, and any unexpected+unexplained behavior should be considered a bug. I ran into an issue today where my home server was running out of space. `df -h` showed I was using 172/200GB. I set this up months ago, there were no other partitions, and there's no reason I would've intentionally created a partition smaller than the disk, so I assumed I must've used a 200GB drive I had lying around for some reason. I probably never checked after the install because I (incorrectly) assumed everything went fine. I also definitely just went with the defaults during install because it's been a while since I did full-time production work on a "regular" Linux server and not just a VM sitting in some giant tech company's server farm.

Anyway I went out bought a new 4TB HDD, then through the hour-long process of dismantling my home network rack to get the PC case out, only to pop it open and find a 1TB HDD already in there! I was lucky to find https://askubuntu.com/questions/1269493/ubuntu-server-20-04-1-lts-not-all-disk-space-was-allocated-during-installation, which explained what happened. In the end, it was a 30 second fix, but I lost about 4 hours on the wrong solution because I never imagined default configs would unexpectedly leave 3/4 of my disk unused. The LVM snapshotting feature seems interesting, but also seems like it requires some manual initialization, and I don't see there being much use in it when a proper backup solution should be using a separate physical disk anyway.

tl;dr I agree with others - the user should be able to make an informed choice during install.

LVM is the default chosen by the subiquity installer. When a user select "use the full volume" this is exactly what he expects. Any other assumption about how users want to use their LMV volumes is bound to turn out false.

LVM allows to downsize volumes when needed (after shrinking the partition with resize2fs). There is no real need to leave spare room in the installation process.

Especially on small drives like a 64 GiB USB stick the current behavior is a nuisance.

I just ran into this bug in production, woke up to a whole series of alerts from my server last night.

Sadly I was expecting it to have 2tb not 100gb so I had no idea my disk would fill up so fast and my important services were therefore not running this morning.

I had no idea my choices during the install screen would not be honoured.

Please seriously consider if you should at least warn the user that this is what you are doing? I much prefer my computers to be doing what I told them to, not mistrusting me to the point of causing an issue.

Thanks a lot.

This behavior is unexpected and wrong. I agree with other comments: if you want free space on your drive, you can ask for it during installation or free it up later. That should not be the default.

Agree that this is unexpected and undesired behavior -- and at the very least needs better phrasing to show that space is being reserved and to explain why.

There are many use cases for LVM beyond snapshots — including easy volume expansion for VM and SAN volumes, where snapshots are likely to be a low priority.

Each time I install Ubuntu I get confused by this and wonder what has gone wrong then I remember that the use entire disk option is only using half the disk.
Most often these days Ubuntu Server is being installed as a VM so snapshotting is completed outside of the host environment and if you create a 120GB virtual disk and say to use the entire disk you would expect it to do just that, not to use 50% and leave 50% unusable (which it is until you create a second partition).

Currently the default option to use the entire disk utilises half the disk and leaves the rest unconfigured.
It should either just use the entire disk as implied or provide an option to either use the entire disk with 1 partition or the entire disk with 2 partitions, that way still using the entire disk and it could promote the reasons to use each option.

It's like a road diversion that doesn't tell you how to get back to the main road again.

I wonder how many confused people have searched for why this is happening. Unless you are trying to confuse the userbase this should be improved.

I agree with the comments above.

An option labelled "Use an entire disk" should use the entire disk.

Just adding another note here: this is a bug, and it has existed for going on four years now. When I tell something to use the whole disk, it should do so. If you want to communicate something along the lines of "golly, why would you use LVM unless you want to take snapshots," you should do so. As others have pointed out, there are other reasons to use LVM.