On Tue, 16 Jun 2009 15:58:37 +0200 Philipp Riegger <li...@anderedomain.de> wrote:
> > On Tue, 2009-06-16 at 16:45 +0300, Daniel Iliev wrote: > > DRBD is HA solution which is achieved by switching the role of the > > nodes in case the "active node" goes offline. I think DRBD is not > > meant for the schema OP has described, because only the "active > > node" is accessible via FS. DRBD works between the FS and block > > device layers. It catches the FS writes from the active node and > > sends them over the network. DRBD on the backup node receives those > > and replicates them directly to the disk driver. Thus you can't > > have mounted FS on the backup node. If the active node goes > > offline, the backup node takes over which means DRBD switches roles > > and the FS has to be mounted afterwards. > > But that might be a good solution with 2.6.30, NFS and FSCACHE. > Sorry, perhaps I'm missing something, but I couldn't understand the solution you had in mind. I'm just saying that the only scenario I have some experience with is DRBD + ext3 and it won't work for load balancing. If "LAMP A" and "LAMP B" as shown on the OP's schema were connected via DRBD + a conventional FS (ext/xfs/reiser/etc.), then only one of those systems would be able to serve client requests at a given moment. -- Best regards, Daniel
