[PVE-User] pve-user Digest, Vol 27, Issue 1

[Fabien Bagard]

> Hi,
>
>  
>
> Apologies if this has been covered recently/elsewhere, but I've had a good
> search on the web and can't find the details I'm looking for - so any
> advice/details would be much appreciated.
>
>  
>
> I'm new to Proxmox/OpenVZ, and to DRBD (and Heartbeat etc), but I am a
> C++/java developer and know Linux fairly well.  I'm looking to set up a
> couple of identical Dell servers with Proxmox, and each has a smallish
> (160GB) disk and a 1TB disk.  What I'd like to do is set up the 1TB disk as
> a dual primary DRBD device, which seems easy enough, and use this for all
> virtual machines (which will be using OpenVZ, not KVM) - not necessarily for
> an active/active setup, but more for backup purposes, so that the up to date
> data is always accessible on the other node if one of them fails (hence my
> preference for dual primary DRBD - so that the data is immediately available
> without having to worry about heartbeat/failing over nodes etc).  I might
> want to put some data in a proper shared directory e.g. web pages that can
> be served by more than one Apache instance, but initially I'd like to take
> having a proper active/active setup out of the equation.
>
>  
>
> I understand that I need a clustered file system on top of DRBD for a dual
> primary configuration, and the popular choices seems to be either GFS or
> OCFS2.  What I'd like to know is, is this easy to do in Proxmox (running
> OpenVZ containers), is GFS preferable to OCFS2 or vice versa, and does
> anyone have any example configuration or notes on how to do it?  I've also
> read that OpenVZ requires ext3 as a filesystem, but looking at the
> documentation, it seems that this is only a recommendation (if you want disk
> quotas) - is this correct, or am I missing something?  Are there any gotchas
> in using GFS or OCFS2?  Can disk quotas still be used in OpenVZ with either
> GFS or OCFS2?
>
>   
I had some problem with an OCFS2. The problem was the disks doesn't sync 
fast enough (writing a huge number of small files very often) that 
caused the FS appeared to be full when it remains 30% free. That's why I 
prefer GFS2

But for PVE, OCFS2 is far more simple to set up and will be a good choice.
>  
>
> I've seen the DRBD howto in the Proxmox WIKI, but this seems to be
> specifically for KVM based VEs (and doesn't use GFS/OCFS2, which is odd as
> the DRBD instructions say this is a necessity for a dual primary
> configuration). 
This is because LVM based disks are used. LV are virtual disks and not a 
file on a file system.

>  I've also seen numerous web pages on setting up a
> primary/secondary DRBD solution with HA/Heartbeat, but nothing on setting up
> a dual primary DRBD device to be used as I've described.
>
>  
>   
Check the drbd official website they have good tutos on how to set up 
drbd + [GFS2|OCFS2]

> Many thanks in advance,
>
>  
>
> Gary
>
>
>   

-- 
Fabien Bagard
Fabien.Bagard at Intersec.com
Tel: +33 1 5570 3349
Mob: +33 6 8777 8300
Fax: +33 1 5570 3332
37 rue Pierre Lhomme
92400 COURBEVOIE