[KLUG Members] Server Mirroring

[Jeremy Leonard]

> > The software I want to mirror is Novell GroupWise.
> > I think I've found a solution. DRBD.
> > This will create a virtual block device that will mirror the data between two servers.
> >
>But don't block devices exist below the locking layer?  Most engines
>cache data, so if multiple engines are sharing the same block devices
>and are not somehow aware of each other your data will probably be
>turned into sticky-paste in short order.

The virtual device can only be mounted on one system at a time. So, only one engine can write data to it at a time. DRBD only alows one system to mount the device.

>
>Replication is not the problem,  replication+concurrency is the problem.
>
> >  This is below the file level.
>  > This coupled with HeartBeat should do the trick.
>
>Doesn't groupwise offer some kind of 'forest' technology within itself?

Novell's recomendation is a SAN.