[linux-lvm] Mirroring a Drive for load-balancing AND failover

[Matthew Gillen]

Fury wrote:
> I've racked my brain on this one, so hopefully someone will be of some help.
> 
> I'm trying to set up two servers which share a drive and do not have a
> Single Point of Failure.  They are on a local network with each other.
>  The best solution would be to have /dev/sda1 on one server mirrored
> with /dev/sda1 on the second server.
> ...
> A second solution was to use GFS/GNBD.  I can export each drive to the
> other server, and do RAID 1 (on both servers) between the local
> /dev/sda1 and the remote gnbd device.  I then format the raid device
> with GFS so both servers can mount it.
> 
> Surprisingly, this last system works.  Both systems can mount the
> drive and read-write to it.  However, if either server in this
> configuration drops dead, the other server cannot deal with the dead
> gnbd device, and the raid device and mount point are no longer usable.
>  I'm sure there are numerous other problems with this setup, also.
> 
> So I'm looking for ideas.  With two servers, how can I mirror a drive
> in real-time, and allow for failover?

You might want to use something more like iSCSI + RAID:
http://linux-iscsi.sourceforge.net/

--Matt