[SOLVED] How to provision a new drive with LVM Thin?

[verulian]

I've installed a new 1 TB SSD into my Proxmox server and have become a bit confused after reviewing the instructions, wiki, etc.

As far as this goes, I would like to have minimal virtual machine storage consumption (ie, I don't want to allocate an entire storage space of 200 GB for a VM initially while I could just use what is needed as it grows possibly up to that point). From what I understand I thought an LVM Thin type storage should be used. I also thought I understood the process to be to create an LVM and then to convert it to a Thin type, etc. This is where I got hung up.

Could someone provide the actual steps for creating such an arrangement to provide a storage device that I can store virtual machine images on in Proxmox 6 that would be growable on an SSD drive like this?

 

[verulian]

Please tell me if the following makes sense. I pulled this from a couple different tutorials, in this case I'm only using /dev/sdb at my 1TB SSD:

fdisk -l # list disks
fdisk -c -u /dev/sdb # create a partition with dos compat off and u gives sectors instead of cylinders, do the following commands inside:
$ n
$ p
$ 1
$ <enter>
$ <enter>
$ t
$ 1
$ 8e
$ p
$ w

fdisk -l # verify drive looks good

pvs # get's physical volume sizes

pvcreate /dev/sdb1 # make the physical volume

vgcreate ssd_vg /dev/sdb1 # create volume group

vgs -v # check things out
vgdisplay ssd_vg # more volume group info

lvcreate -L 900G --chunksize 64K --thinpool ssd_guests ssd_vg
(can remove with: lvremove ssd_vg/ssd_guests)

mkfs.ext4 /dev/ssd_vg/ssd_guests # format ext4

mkdir -p /mnt/ssd_guests # make mount point

mount /dev/ssd_vg/ssd_guests /mnt/ssd_guests # mount it

lvdisplay ssd_vg/ssd_guests # take a look see

#add it to /etc/fstab for automounting at boot:
echo "/dev/ssd_vg/ssd_guests /mnt/ssd_guests ext4 defaults 0 2" >> /etc/fstab

 

[verulian]

I guess the question is that after I create this, how do I get it to show up for storage? I can't seem to get this to show up anywhere to actually USE it now.

 

[verulian]

Unfortunately I found that after reboot and having that line in /etc/fstab the system will not boot. I had to go into single user mode and comment out that line. I even tried to use the UUID insetad of the dev path. It seems that I can mount it fine manually, but automounting it doesn't work. And then of course there's the problem of seeing it in the system too as per above.

 

[verulian]

So I'm still having some trouble here. I found some quite old instructions that were interesting: https://proxmoxve.blogspot.com/2013/12/how-to-add-extra-storage-in-proxmox-ve.html

I deleted my LV "ssd_vg" so that I was back to just a VG of "ssd_vg", but when I went to Datacenter > Storage > Add, I did not see this "ssd_vg" listed in the "Volume group" dropdown - only "pve" is in there.

I am guessing that if Proxmox could detect the VG "ssd_vg" that I made that I could add this as an LVM and THEN maybe be able to create an VM Thin entry from this?

Any additional insight would be wonderful...

 

[verulian]

I found this post: https://forum.proxmox.com/threads/cannot-add-lvm-thin-storage-to-gui.50200/

Which basically says to back out of everything and do this via the Proxmox Web GUI.

So I removed the /etc/pve/storage.cfg entry that I'd tried to make for the thin-lvm, I also issued the following again to wipe out all LVM stuff:
lvremove ssd_vg/ssd_guests
vgremove ssd_vg
pvremove /dev/sdb1
cfdisk /dev/sdb # and I deleted the partition, wrote it and quit
# and rebooted

When I brought the system back up, I went into the node where this is installed and under Disks I found I could go to LVM-Thin and was able to create it from there.

I thought I'd try to examine what was done so I just poked around a bit:
pvs showed the physical volume:
/dev/sdb ssd_guests lvm2 a-- 931.51g 0
vgs showed the volume group:
ssd_guests 1 1 0 wz--n- 931.51g 0
lvs showed the logical volume:
ssd_guests ssd_guests twi-a-tz-- <931.28g 0.00 10.41

I thought it was interesting that Proxmox just names the group and logical the same.

I then checked out /etc/pve/storage.cfg to see what was going on:
lvmthin: ssd_guests
thinpool ssd_guests
vgname ssd_guests
content rootdir,images
nodes pve

I see that "ssd_guests" is now showing up in the Datacenter > Storage tab as "LVM-Thin" for Disk images and Containers. It does not, however, seem to have a Path/Target definition. Should it? I'm not sure how to access it from the shell now if I need to do anything unless I manually mount it.

 

[chevybeef]

I found this post: https://forum.proxmox.com/threads/cannot-add-lvm-thin-storage-to-gui.50200/

Which basically says to back out of everything and do this via the Proxmox Web GUI.

So I removed the /etc/pve/storage.cfg entry that I'd tried to make for the thin-lvm, I also issued the following again to wipe out all LVM stuff:
lvremove ssd_vg/ssd_guests
vgremove ssd_vg
pvremove /dev/sdb1
cfdisk /dev/sdb # and I deleted the partition, wrote it and quit
# and rebooted

When I brought the system back up, I went into the node where this is installed and under Disks I found I could go to LVM-Thin and was able to create it from there.

I thought I'd try to examine what was done so I just poked around a bit:
pvs showed the physical volume:
/dev/sdb ssd_guests lvm2 a-- 931.51g 0
vgs showed the volume group:
ssd_guests 1 1 0 wz--n- 931.51g 0
lvs showed the logical volume:
ssd_guests ssd_guests twi-a-tz-- <931.28g 0.00 10.41

I thought it was interesting that Proxmox just names the group and logical the same.

I then checked out /etc/pve/storage.cfg to see what was going on:
lvmthin: ssd_guests
thinpool ssd_guests
vgname ssd_guests
content rootdir,images
nodes pve

I see that "ssd_guests" is now showing up in the Datacenter > Storage tab as "LVM-Thin" for Disk images and Containers. It does not, however, seem to have a Path/Target definition. Should it? I'm not sure how to access it from the shell now if I need to do anything unless I manually mount it.

Thanks for this it was most useful. I was trying all sorts of things until I reverted disk changes, went to the node, LVM-Thin and Create.