On Fri, Jun 04, 2010 at 11:06:52AM -0600, Jason J. W. Williams wrote:
> Dang. We've already started the implementation of HAProxy, and would
> prefer to only have one SLB solution.
You see, there's never an absolute *one* SLB solution :
- you may have layer2 load balancing (etherchannel, bonding, ...) at
several places on your network ;
- you may have layer 3/4 load balancing on several systems (dedicated
LBs, firewalls, servers, outgoing link load balancing)
- you may have proxy-based L4 load balancing for some services which
may be offered by a variety of solutions.
- you may have HTTP load balancing on some systems and performed by
different products (pound, haproxy, nginx, ...)
- you may have non-HTTP L7 load balancing on other systems assured
by very different products.
- you may even be using DNS load balancing for multi-site or faster
page loading in your visitors' browser.
In fact you can run load balancing everywhere with many different tools.
Trying to centralize everything on one single solution for the sole purpose
of running only one solution is the worst thing to do, as you are certain
not to be 100% satisfied, whatever the solution.
"The right tool to get the job done right"
If you look at commercial offerings, you'll see that up to 2-3 products
are combined to get the job done right. Exceliance's ALOHA Load balancer
involves haproxy for layer 4-7 and LVS for layer 3-4. Loadbalancer.org's
appliances uses the same and adds pound into the mix. Yes there is a big
intersection area between these tools. But in the end the overall quality
benefits from these choices and that's less stress for the admin because
each tool does its job right and is used where it performs best.
So don't be afraid of combining two simple solutions to perform two
different things, that will simplify your configurations, architecture
and troubleshooting.
Last, keep in mind that most products will generally score more than 2/4 on
the following criteria, which means that you can hardly improve one without
degrading the other ones :
- simplicity
- features integration
- reliability
- efficiency
Haproxy is no exception, version 1.3 got more bugs than the more limited
version 1.1, configurations for new versions are harder to understand than
old ones, and the optimisations bringing its efficiency has definitely
impacted reliability a few times.
Thus, make your choice, but if I were you I'd pick the tools I need and
not the tool that does everything.
Regards,
Willy
