Subject: Re: [vserver] Re: [Freedombox-discuss] [vserver] Re: A software architecture for the FreedomBox
From: Martin Fick <mogulguy@yahoo.com>
Date: Fri, 15 Apr 2011 08:36:38 -0700 (PDT)

 Fri, 15 Apr 2011 08:36:38 -0700 (PDT)
--- On Fri, 4/15/11, Jon Bendtsen <jbendtsen@laerdal.dk> wrote:
> On 15/04/2011, at 01.01, Martin Fick wrote:
> > Think load balancing.  Say 10 vservers, split
> them
> > so that 5 run on each host normally.  If either
> host
> > goes down, the other one picks up the slack.
> > Everything runs slower, but at least it still runs.
> 
> I think about the same considerations at the moment,
> planning a new setup.
> 
> Why not make 2 DRBD shares, A and B, put half of the
> vserver guests on the A storage, unify, them, and then put
> the other half on the B share. All the vserver guests on the
> A DRBD share runs on the A-host, and like wise with the B
> host. In daily usage you have no open files from the B share
> on the A host, so all the memory would be unified. In case
> of a split brain you can keep the guests running, and once
> you get connection again easily resync the DRBD.
> 
> In case of 1 vserver host failing then you can just start
> all the vserver guests in DRBD share A on the vserver host
> B. Yes that will not unify both groups of hosts, but that
> should only be until you get the A host up again.
> 
> So, what do you think?

Sure, I think it would work.

But it is less than ideal, and for me, it requires 
too much of a commitment to a "hack" setup, or half 
way solution, which is too inflexible.  I prefer to
incur the memory penalty.  It really is much easier
to manage all the servers independently, or as one.
Making an arbitrary split is more complicated.

-Martin