DRBD9 without thin provisioning

[Kei]

Hello,
I'm following the tutorial at https://pve.proxmox.com/wiki/DRBD9, but it seems that I'm only allowed to use thin LVM's, and not thick provisioning. In fact, the command you're suggested to type is:
root@proxmox:~# lvcreate -L 511G -n drbdthinpool -T drbdpool
Is it actually possible to create a "thick" LVM? If so, how should I edit this command?

 

[dietmar]

Our backend requires that you use a thin pool, because you cannot create snapshots/clones without. What exactly is the problem?

 

[Kei]

Thank you for the prompt reply. I come from an environment where I used LVM's on a single PVE node, so DRBD, ort any replication system, was not required. At that time, I used Thick LVM's over Thin LVM's because I don't need to allocate more space than it's required; infact, I would prefer to have a fixed size for my guest images, so that I can't overprovision space in any circumstance. If it's only possible to have thick provisioning with DRBD9, I guess I will deal with it, but I just wanted to be sure that it's not possible otherwise.

 

[Kei]

Please help. The support for thin provisioning in DRBD9 seems to be not stable enough, as declared by them. As a matter of fact, I lost a test VM few hours after creation, and they say that this is possible. However, thick provisioning with DRBD9 is considered to be stable. So, I really cannot use it in PVE?? I don't need snapshots/clones. If thin provisioning is the only thing comphatible with DRBD9 in PVE, I have to switch to ceph. Please advise!!

 

[jeffwadsworth]

Please help.

Is there any particular reason why you need to use DRBD9 vs CEPH? CEPH is integrated pretty well into Proxmox.

 

[Kei]

Actually just the fact that I wish to run a three nodes cluster but the third node should be just for quorum but Ceph will require to set up data storage for this node too. Not a huge deal I guess. Another problem is that I cannot assign a full disk to Ceph, only partitions. This is because I'm limited to one single SDD per node. Would this be a problem? Also, Ceph is intended for massive scalability if I understands correctly so I thought I would be a waste for me. Not to mention that it sure is more complicated but hey, in not afraid to learn

 

[Kei]

Ok I reply to myself: apparently the PVE implementation of Ceph only allows you to use whole drives, and not just partitions. That's going to be an issue because I'm not sure if I can afford two more SSD's, it's just an home setup. I need to check the fesibility of using USB sticks to boot PVE.