[PVE-User] Proxmox and DRBD

[Yannis Milios]

Both drbd8 and drbd9 can be configured in pve without issues. The former,
can be configured in pairs of two pve nodes, where for the latter, three
pve nodes is the minimum.IIRC drbd8 kmod is included by default in the pve
kernel, so you will only need to install drbd-utils to get started.
For drbd9, follow the instructions as described in Linbit's
documentation.In my opinion enabling HA in just 2 pve nodes, with drbd8 in
dual primary mode, is just too dangerous.As a minimum, proper (hardware)
fencing must be configured in both drbd and pve to avoid data corruption.