[DRBD-user] DRBD/Linstor/Proxmox diskless storage-pools

[Rob Tongue]

Greetings!

I have been trying for some time to solve this, hopefully someone here 
can help.  I currently have a working three node proxmox/drbd/linstor 
cluster, but have an interesting use case in addition that I cannot seem 
to make work.

One of the 3 nodes has a large amount of spinning disks that I would 
like to use throughout the cluster as well, but I have no way to 
replicate that storage to the other two.  So I want to use two of the 
three nodes as "diskless" clients, while only the one node provides 
actual storage.  I do not care about redundancy for this storage 
instance, I only want to be able to mount the storage from any node, 
mainly because the two without the storage are more powerful machines as 
far as CPU and memory are concerned, but do not have the ability to host 
the actual storage.  I understand it is not ideal, but in this home lab, 
it is all I have.

I could use NFS for this, but would rather use drbd, as I am fairly 
certain it would perform better due to the nature of the raw storage, 
rather than qcow2 images.

So here is what I have tried:

I have created as a test, a small lvm thinpool as a storage-pool on node1

# linstor storage-pool create lvmthin tank1 test test/pve

Then I created on tank2/tank3 diskless storage-pools.

# linstor storage-pool create diskless tank2 test
# linstor storage-pool create diskless tank3 test

This is the result:

# linstor storage-pool list
┊ StoragePool ┊ Node  ┊ Driver   ┊ PoolName      ┊ FreeCapacity ┊ 
TotalCapacity ┊ SupportsSnapshots ┊ State ┊
╞═══════════════════════════════════════════════════════════════════════════════════════════════════════════╡

*snip*


┊ test        ┊ tank1 ┊ LVM_THIN ┊ test/pve      ┊ 4.98 GiB ┊      4.98 
GiB ┊ True              ┊ Ok    ┊
┊ test        ┊ tank2 ┊ DISKLESS ┊ ┊              ┊               ┊ 
False             ┊ Ok    ┊
┊ test        ┊ tank3 ┊ DISKLESS ┊ ┊              ┊               ┊ 
False             ┊ Ok    ┊
╰───────────────────────────────────────────────────────────────────────────────────────────────────────────╯

I then created the resource group:

# linstor resource-group create --storage-pool test --place-count 1 
--diskless-on-remaining test

(For clarity, I am not sure what to put for --place-count, so I tried 3 
as well with the same result.  I also tried without 
--diskless-on-remaining... same.)

Then I finally created the volume-group

# linstor volume-group create test

When adding this storage to proxmox's storage.cfg, I lose the web 
interface of proxmox, and refreshing the page only provides the 
Datacenter top level section in the left pane, with nothing underneath 
it.  No nodes or anything.  Removing the storage.cfg entries, makes it 
all come back.  Very strange, and want to verify I did everything correctly.

drbd: test
     content images,rootdir
     controller 10.128.1.100
     resourcegroup test
     controllervm 100

Any ideas? Thanks in advance.

-phunyguy