[PVE-User] DRBD & Proxmox scenario

[Dmitry Petuhov]

09.03.2015 20:33, Gilou wrote:
> Hi,
>
> I've been reading all the documentation about Proxmox & DRBD, and I have
> questions for those who might have deployed such a setup.
>
> The idea is to run 3 nodes on similar hardware, and to begin, host the
> disks on 2 of the nodes using drbd.
Strange setup. What third node will do? DRBD is (was?) good for 2-node setups. If you have 3 nodes, you'd better look at ZFS (if you need OpenVZ) or CEPH (if you don't need OpenVZ or ready to setup cephfs on nodes manually).

> The wiki reference here is the most extensive info:
> https://pve.proxmox.com/wiki/DRBD
>
> Which seems to point at the idea of having 2 LVs, one for each node to
> host the VMs that will "mostly be on the node", and let drbd do its
> magic as single primary setup.
>
> It seems that the current way of doing things. I'm not too much a fan of
> this idea, as it makes the nodes more "powerful" than they should be in
> a cluster. If this is still "how things are done", so be it.
>
> So how to go for dual primary setup? It seems GlusterFS & OCFS2 aren't
> really neatly supported, but without a clustered filesystem, what to do?
Dual-primary DRBD was pretty unstable few years ago. Even without filesystem (as LVM storage like in wiki). Adding filesystem layer will add its bugs to setup.

> Ceph doesn't seem any more ready for show time, and it doesn't seem like
> a good idea to run it off proxmox nodes atm?
>
> I only dealt with storage outside of Proxmox until now (using drbd,
> btw), but I have a case where I'd like to avoid having to put on a
> separate setup for it, and am left wondering.
Just look at other storages. DRBD isn't what you want for >2 nodes.