Change current dual boot partitions or fresh reinstall Lubuntu with Windows VM?

[Dennis N]

QUESTION: I am thinking that since LVM can be modified on the fly, I may be able to set up my LVM with my current Lubuntu/Windows 10 dual boot, rather than wipe out the Lubuntu and Windows > then set up my LVM > then install Lubuntu and Windows. Is this correct?

If this is correct, do you (or others) have any suggestions as to how to do this without screwing up my present dual boot?

I don't think you can convert your existing Lubuntu with standard install on a partition to an LVM installation, if that's what you are thinking. (If so, I would be interested in learning that process).

You can add a partition for LVM use to your existing disk, space permitting. That's how I began learning LVM - just one partition for experimenting with an LVM installation and the LVM commands. The existing installs are not disturbed, and all can be in a multiboot setup.

[TheFu]

There is no migration of already installed OS on partitions to LVM method. A fresh install is needed. However, many backup/restore processes are storage agnostic, so if your backup/restore process isn't tied to the actual storage used, then switching should be possible in less than 1 hour.

For unencrypted OS installs, I prefer to setup my LVM layouts using a script between the ISO boot and storage "Do Something Else" options. Basically, I switch to a different tty and use scp to pull the script to the machine being installed and manually use CLI tools to partition, create a PV, VG, then the LVs that I want, add some labels to help keep the purpose known in my mind, and finally toggle back to the installer and "Do Something Else" ... where I connect each partition and LV to the specific storage for the system. Then the installer goes and finishes. Https://ubuntuforums.org/showthread....4#post14053144 is a reference. Just forget the LUKS encryption aspects. I find the 20 lines in my script that I manually tweak are easier than all the nasty point-n-click the installer requires to do anything with LVM. Just connecting pre-existing LVs is a hassle, but only needed once as part of the install process. It is nice to have these things setup and used by the installer, so I don't need to go back, resize LVs, create some others, and mount them as I really desire. Finally, having to move data from the installed locations (/var and /home) in to the new LVs is a bit of a hassle. By setting up the LVs before installation, I avoid that.

Also, if you have existing UEFI partitions, then you don't need to create or touch those. They should be recognized by the installer. However, they may need to be resized/moved. YMMV. Ubuntu seems to think we need 500MB for UEFI. I don't know why.
On a 22.04 system default ZFS install, they allocated 512MB, but it is only using 17MB.
On a 20.04 system where I controlled everything, I allocated 50MB, but it is only using 6.1MB. Across all my UEFI using systems, I've never needed even 50MB for that partition.

[AbleTassie]

The good news is that LVM is LVM regardless of distro. The core commands used are the same to create, resize, move, change across all distros for at least the last 20 yrs. A few options have been added, like for LVM-RAID, but most people wouldn't use that.

In a single disk setup, LVM is pretty simple.

Thank you for your comments as always Fu. I hope to eventually start using LVM after some study so I know what I am doing. Just one more question for you or others. It seems to me that a GUI for LVM would be helpful for beginners. I have found a December 2020 article on GUIs for LVM that can be used for the Linux OSs, How To Use GUI LVM Tools by Ares Lee in the Linux Journal see link. I have copied & pasted a table from the article that compares and contrasts such GUIs for LVM. It is underneath my username below.

QUESTION: Can you recommend a GUI program for LVM that can be used with Ubuntu that is free?

Thanks again,

Able

Table from article How To Use GUI LVM Tools :

Features	LVM GUI	Blivet-gui	GParted	YaST Partitioner	KVPM	Visual LVM
Platform	rhel/centos *	centos 7+ *	*	opensuse	*	*
Disk Operations	no	yes	yes	yes	yes	no
Create PV	no	yes	yes	yes	yes	yes
Resize PV	no	yes	yes	no	yes	yes
Delete PV	yes	yes	yes	yes	yes	yes
Modify PV Settings	no	no	no	no	no	yes
Migrate PV	yes	no	no	no	yes	no
Create VG	yes	yes	no	yes	yes	yes
Delete VG	yes	yes	no	yes	yes	yes
Append/Reduce PV	yes	yes	no	yes	yes	yes
Config w/ create VG	yes	PE Size only	no	PE Size only	PE Size only	yes
Rename VG	no	no	no	no	no	yes
Modify VG Settings	no	no	no	no	no	yes
Backup/Restore VG	no	no	no	no	no	yes
Create LV**	yes	yes	no	yes	yes	yes
Resize LV	no	no	no	yes	yes	yes
Delete LV	yes	yes	no	yes	yes	yes
Rename LV	no	no	no	no	yes	yes
Modify LV Settings	no	no but has menuitem	no	no	Some	yes
Format LV	yes	yes	no	yes	yes	no
* means support multiple platforms
** the supported logical volume type :

Supported Volume Type

	LVM GUI	Blivet-gui	GParted	YaST Partitioner	KVPM	Visual LVM
Simple/Linear	yes	yes	no	yes	yes	yes
Stripe/RAID0	yes	yes	no	no	no	yes
Mirror/RAID1	yes	yes	no	no	yes	yes
StripeMirror/RAID10	no	no	no	no	no	yes
RAID4	no	no	no	no	yes	yes
RAID5	no	no	no	no	yes	yes
RAID6	no	no	no	no	no	yes
Snapshot	yes	yes	no	no	yes	no
Pool	no	yes	no	yes	yes	no

[TheFu]

I've never used any GUI with LVM. Most of my systems don't have any GUI at all.
LVM on Linux works the same as LVM on Unix. The big ideas are all the same. So, if you've ever used VeritasVM/FS, then their isn't much of a learning curve.

The real key to understanding LVM is that everything pivots around the VG, Volume Group. PVs can be added to a VG. LVs are pulled from an LV and depending on the number of PVs and the amount of free storage in each will determine whether you can have striped, RAIDx or concatenated LVs. Basically, with 3 different types of objects, LVM is extremely flexible. OTOH, just because something CAN be done, that doesn't make it a good idea. For example, I don't have LVs that cross multiple disks unless they are RAID1. That's because I was burned doing that about 20 yrs ago. I'd merged 3 disks (PVs) into a single VG and kept expanding the LV. Then 1 of those disks failed and all the data on all three disks became unavailable. I probably have those 3 disks on a shelf somewhere. Maybe the data can be restored with 20 yrs more knowledge, but at the time I didn't have that ability.

[AbleTassie]

I have a basic understanding of LVM and it certainly seems pretty simple and like a powerful tool and approach as opposed to the: "conventional" approach of physical volumes (devices) with essentially physical partitions within the physical devices, and (I think) what amounts to logical volumes within separate partitions. And I appreciate Fu's caution about being careful about (or not) using LVs across multiple physical volumes or disks.

For a beginner, I think that use of a GUI with LVM might be helpful and prevent mistakes early on. I think it will take a while longer, playing around and experimenting for me to get comfortable with LVM.

The responses here have helped me think about the best approach the situation prompting my original query: Change current dual boot partitions or fresh reinstall Lubuntu with Windows VM? I am starting to think more about Backup of my Home folder and some of the other suggestions early on in the thread as important to do.

So thanks to everybody for their posts, answers and replies: I think you have informed me further about my situation. I am going to mark this thread as SOLVED.

Thank you,

Able

[TheFu]

LVM can do so many things that are nearly impossible for any GUI to capture in a useful way. A GUI would just handle the most trivial 20% LVM setups, which hardly makes having the GUI useful.

As you learn more about LVM, you'll come to understand better.