I think the better question is this.  How can I make my 2 physical servers that are identical into the best clustered solution sharing the storage between the 2. 
Server 1 is the main server and server 2 is the backup server.
This is my set up now.
Each is running Centos 5.3
I have virtualization set up on them so this is the setup:

Dom0
These are the quests.
  1. Samba 1 with 3 terabyte block device
  2. Samba 2 with 2 terabyte block device
  3. Samba 3 with 2 terabyte block device
  4. Lotus Domino 3 terabyte block device.
They all use xfs.
I want to keep the guests the same on each server.
I will start with the backup server. I will go on each vm and delete this FS and block device.
I then want make that whole 10 terabyte raid into one gfs and then re-attach it back to each guest. 
Is that possible or do I have to start all over again?  If it can be done I then will sync the date from the mainserver to this backup server and then switch them and do the same to the mainserver. 

I have one more question which is another whole thread.
I am using rsync to sync the 2 physical boxes now.  Is there a better way to do this?


On Tue, Feb 9, 2010 at 10:23 AM, Ben M. <centos@rivint.com> wrote:
Rich wrote:
> I want to make the 10 terabytes raid an xfs filesystem and then share
> the drive with all 4 of the vm's.  3 of the servers will be samba
> servers and one will be my Lotus notes server.  I want to make the
> filesystem /data and then each one of the servers will use specific sub
> directories.  I have it set up as block devices now but I want the
> flexibility of having the whole 10 terabytes available to all 4 servers.
>
> On Tue, Feb 9, 2010 at 1:28 AM, Christopher G. Stach II <cgs@ldsys.net
> <mailto:cgs@ldsys.net>> wrote:
>
>     ----- "Adam Adamou" <adam0x54@gmail.com <mailto:adam0x54@gmail.com>>
>     wrote:
>
>      > either nfs or ocfs2. nfs is the easiest route. ocfs2 will give you a
>      > clustered filesystem.
>
>     Except NFS doesn't follow normal filesystem semantics and you can
>     end up with corrupt data without knowing it, and it, along with
>     CIFS, will give you a free shitload of network overhead to go along
>     with your possibly corrupt data. OCFS2 or GFS are the only practical
>     choices if you want it to behave like a typical filesystem and not
>     have to worry about catering to it or rewriting software and/or
>     reeducating developers, and OCFS2 is extremely easy to set up.
>
>     The original question didn't specify much about the requirements,
>     though. A single shared filesystem? Read-write or read-only? No
>     filesystem at all? Without that information, I would at first
>     recommend not sharing. It can be a lot of trouble, it's usually not
>     required, and it severely complicates life when things fail.
>
>     Well, there is always XenFS... :/
>
>     --

Though dated, this article is interesting regarding this thread. The
article needs to be updated (Last Modified = June 2006), and rewritten
for CentOS Xen virtualization, but it looks sound upon my first reading:

<http://xenamo.sourceforge.net/>


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