[PVE-User] Is there any problem using DRBD over LVM?

[Gilles Mocellin]

Le 08/11/2012 15:44, Flavio Stanchina a écrit :
> Gilles Mocellin wrote:
>> Not in a proxmox context, I also had to answer that question.
>>
>> I used DRBD over LVM.
>
> How did you then split up the DRBD volume between VMs? Did you 
> configure a dedicated DRBD resource for each VM?

>
> (or maybe "not in a proxmox context" means there were no VMs involved 
> and you just used the whole volume for one application, in that case 
> ignore these questions)
Yes, in fact, it was not used for VMs, but If it was, I would have 
configured a dedicated DRBD resource.
>
>> I think it's the easiest way to handle resizing. I didn't have to
>> allocate a whole partition.
>> I can use only a small LV to begin, and resize if necessary after. Or
>> create another LV for another DRBD volume...
>>
>> Anyway, what would be difficult to handle is LVM over DRBR over LVM ! 
>> >:o
>
> I once configured LVM over DRBR over LVM (on  Proxmox 1.x) and it 
> worked pretty well, it's the most flexible solution allowing you to 
> move or resize anything with little or no pain. However, eventually I 
> got rid of it because it would have been a nightmare to maintain in 
> case of problems, given the lack of sufficiently skilled Linux 
> sysadmins besides myself.
>
So it is very preferable, if all can be done with the proxmox interface.
With LVM over DRBD, the DRBD layer would be transparent, and the LVM 
well handled by proxmox.

Another point, you need a LVM backend to use snapshot backups.

I hope that really soon, we can use ceph instead of DRBD. More scalable 
(>2 nodes with DRBD ?).
More trendy. More Fun !