[Koha] Load Balancing with Koha

[Dave Sherohman]

On Fri, Dec 07, 2018 at 03:58:15PM +0100, Paul Poulain wrote:
> wow, did you need load balancing for performance reasons, or was it just by
> choice ?

For redundancy.  I can take any involved server down and the rest will
keep running without any interruption of service to the end users.  For
example, the elasticsearch worker nodes ran low on disk space yesterday
(one of the other developers was experimenting with aliased indexes and
made a lot of them in the process), so I've been expanding their disk
allocations today, taking one node down at a time.  I was able to do
this while an external demonstration was being given, plus all normal
usage, with no issues.  If I hadn't told other team members about it,
nobody would have even known.

But, yes, none of the (virtual) machines involved is heavily loaded
under normal circumstances.  They all generally run at 20% CPU usage or
lower with little I/O and network loading as well, and these are
provisioned with 6 CPU cores for the web servers and 2 cores for most of
the rest, so they're also very low-powered servers.  With the available
hardware, I could easily run it all on one box, but, if that one machine
had any kind of problems, we'd be offline until I could fix it.

Plus I also enjoy being able to say that I've designed and built what
just might be the most over-engineered koha system in the world.  :)

-- 
Dave Sherohman