installing ubuntu from bootable usb, using lvm

[Robert Heller]

At Fri, 18 Jul 2025 08:18:15 -0400 "Ubuntu user technical support,? not for general discussions" <ubuntu-users at lists.ubuntu.com> wrote:

> 
> Hi Sam.
> 
> In all honesty, I'm not sure I do (which is why talking directly with
> someone would be seriously helpful).
> 
> I "think" I need LVM in order to be able to "tie" the
> internal/external drives together in a manner that allows the OS to
> reside on the internal ssd, while having the data on the external
> drive. The connection/coupling of the external drive/dirs would be via
> the LVM/symlink process.

No you don't need to "tie" the internal/external drives together. Yes, LVM
*can* be used as a "simple" RAID0-like hack to join two (or more) disks into a
single volume group. But I don't think you really want to do that. Using LVM
that way makes more sense if you have multiple "small" internal disks (or
maybe an external enclosure with multiple "small" disks). Binding an internal
*laptop* disk and with an external disk is just asking for trouble.

You *can* create multiple LVM volume groups. In your case one for the internal 
disk and another one for the external disk.  You can then carve out logical 
volumes for different uses.  Put the core system file systems (/boot, swap, /, 
/var/www, /home, etc. on the internal drive).  This will allow the laptop to 
boot up and be usable without needing the external drive connected.  The 
external drive can be carved up into various data file systems.  You can use 
automount (sudo apt install automount) to mount them on demand.

> 
> And to your point about needed to always then carry the external
> "working" drive or you have a brick, yep!  As I mentioned, fragile.
> 
> If you are in the US/North/South America, let's talk for a min!
> 
> thanks
> -bruce
> 
> 
> On Fri, Jul 18, 2025 at 7:28 AM Sam Varshavchik <mrsam at courier-mta.com> wrote:
> >
> > bruce writes:
> >
> > > So far, haven't found any tutorial with screen shots showing the
> > > Install process invoking the LVM process (volGroup, LogicalVol, etc)
> >
> > Let's take a step back. Why do you believe you need an LVM?
> >
> > > Does anyone have any pointers/sites to illustrate this process?
> >
> > LVM is one of those things which are only needed if there's specific
> > requirement, knowledge, and understanding what an LVM is, what it does, and
> > how it works.
> >
> > Especially on a laptop.
> >
> > > I've seen a few sites that illustrate the partition setup:
> > > example partition
> > >
> > > /dev/sda --- internal 128G ssd
> > >  /dev/sda1  ext4  /boot     1G
> > >  /dev/sda2  ext4  /root     1G
> > >  /dev/sda3  swap           10G
> > >  /dev/sda4  ext4  /       110G
> > >
> > > /dev/sdb --- exetrnal 1TB hdd
> > >  /dev/sdb1  ext4  /etc     1G
> > >  /dev/sdb2  ext4           10G
> > >  /dev/sdb3  ext4  /       110G
> > >
> > > But then the examples, drop into "go ahead and then install"
> >
> > Right, and marry the laptop to the hard drive, forever. Any time you want to
> > take your laptop somewhere you must lug this hard drive with it. Without it,
> > your laptop becomes an unbootable brick. Because it contains the friggin' /
> > filesystem.
> >
> > Because that's how LVM works.
> >
> > So, again, why do you think you need to use LVM?
> >
> > --
> > ubuntu-users mailing list
> > ubuntu-users at lists.ubuntu.com
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> 

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