There is no option in debian-installer to setup an entire (whole) disk as LVM
physical volume (PV).

e.g.: I have two disks (/dev/sda, /dev/sdb) and I want to setup /dev/sdb as a
physical volume (PV) as in 'pvcreate /dev/sdb'. Now, in d-i, I have to create
a partition to make my second disk an LVM PV.

Thank you!

What's so bad about having to create a partition that spans the whole
disk?

I am doing this way right now.

But LVM also allows us to use a whole disk as a PV, so I just wanted to know,
if there are any reasons, we are not doing this way in a Debian. Logically,
it seems, we should use an entire disk as a PV, if we intent to give it to
LVM, anyway.

reassign 418519 partman-lvm
severity 418519 wishlist
tags 418519 wontfix
thanks

That something is possible is not always sufficient reason to add support
for it. I'll reassign your request to the correct component, but I'm also
going to tag it "wontfix" as implementing it would mean more code (which
would need to be tested) without any real benefits.

Maybe others can provide reasons why we should support this.

Cheers,
FJP

Hello,

I can tell example where having raw disk as PV is handy: using hardware
RAID controllers, such as Areca ones.

Raid controllers allows you to add new disks to existing raid array. For
example, if you have Raid 10 using four 1TB disks, you can add two more
disks and increase capacity from 2TB to 3TB.

After raid *online* reinitialization, one can increase volume size inside
that raid array, and system now can see that /dev/sda is incresed to 3TB,
also without downtime (simply after rescanning SCSI).

Now, if you have LVM PV inside partition, you first have to resize
partition first, which will mean downtime and possibly disaster on human
error while fiddling with partitioning tools.

Meanwhile, if PV would be a physical disk, one could simply use pvresize...

When the only disk is "completely LVM",
then boot loaders should also have support for it.

When the computer is "Only LVM" also.


"workaround": use an additional  dedicated boot disk[1]



Groeten
Geert Stappers

Note
[1] something that bootROM ( "BIOS" ) supports

2015.01.02 22:13, Geert Stappers wrote:
to be as "boot disk", containing only boot loader (and maybe /boot), which should not be ever resized or snapshoted or
whatever, no need for LVM.

Second volume (/dev/sdb) would be raw PV containing "/" and other LVM volumes. But I can't implement it simply by using
partman.

Control: -1 - wontfix

Patches welcome

Making way for propellor or/and other changes

Sorry

I would think that having a partition on sda flagged bootable might
be necesary at least on systems.  Many systems over the years have had
BIOS/firmware issues that insisted things had to look a certain way to
be bootable even if that wasn't officially a requirement.  After all
that's how microsoft OSs were always installed, so making assumptions
was often considered valid since it always worked when tested.

So certainly not required, but might be safer.

Also there has to be somewhere to install the bootloader, and blockmapping
into the filesystem is a very bad idea, so having some space set aside
for the boot loader is a good idea (which often ends up being the unused
space of the disk before the 1st partition when doing 1MB alignment of
partition starts).  With EFI you simply have a dedicated mandetory
partition to store the boot loader, but of course then you must also
have another partition for /boot in that case, since /boot has to be a
unix style filesystem, and the EFI boot partition has to be FAT (as far
as I know).

2015.01.03 17:24, Lennart Sorensen wrote:

Uhm, yes, of course. Bootloader is just before /dev/sda1 partition, which may be /boot or a dummy/unused.

Everything in /dev/sda raid volume is "as old school and bootable as should be". Meanwhile /dev/sdb could be advanced,
flexible LVM stuff.

I've just remembered that this wishlist exists... Here I've copied our
server's current layout as motivational example:

$ lsblk
NAME                         MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda                            8:0    0 186.3G  0 disk
└─sda1                         8:1    0 186.3G  0 part
  ├─vg_system-lv_root (dm-0) 254:0    0 168.7G  0 lvm  /
  └─vg_system-lv_swap (dm-1) 254:1    0  17.6G  0 lvm  [SWAP]
sdb                            8:16   0     2T  0 disk
├─vg_data-lv_wal (dm-2)      254:2    0    20G  0 lvm  /media/wal
└─vg_data-lv_data (dm-3)     254:3    0 912.6G  0 lvm  /media/postgresql

There *must* be sba1, because before that partition (which is LVM PV) there
is free space for GRUB to be installed.

For other drive, sdb, there is no need to have sdb1 partition, it's
directly a LVM PV, which can be resized more easily compared to being on a
partition. But d-i does not allow users to do that in preseed.

sdb drive setup is currenly done with post-installation script in our
case...