Suggestions please for load balancers.

Mon Nov 7 14:15:29 PST 2005

On Thu, Nov 03, 2005 at 06:24:40PM -0700, Nicole wrote:

> On 04-Nov-05 My Homeland Security "observers" reported that Jim Dennis said:
>> On Thu, Nov 03, 2005 at 12:07:26PM -0800, Dave Johanson wrote:
>>> Alteons are inexpensive on eBay these days.
>>> If money wasn't an issue I would buy Netscalers.

>>> Dave J.

>>  If money was your prime consideration how would you feel about
>>  roll-your-own with something like IPVS (Linux Virtual Server
>>  Project)?

>>  (Just curious, haven't used one, yet)

> If a gerbal on a wheel was reliable, had good docs and worked I would 
> use it..
> assuming management was ok with it. Any good URL's for it or other
> versions, etc?  

>  Nicole

 My comment was more on the order of fishing for comments from anyone
 who *has* used one of these under fire.

 You can read more about it at: 

     http://www.linuxvirtualserver.org/

 ... but I'd make the following observations before I'd recommend
 them:

    * You might be able to download, configure and install one of 
      these on a set of systems in about an afternoon.  The price
      and availability are right and you don't have to deal with
      slick, verbose, cloying sales critters to play with one.

   * I wouldn't seriously consider proposing this unless you have
     enough spare/idle hardware to set up a three server load balancing
     pool and a small farm of load generators (at least three clients
     --- preferably at least six).

   * The hard part of demonstrating the feasibility of this approach
     is finding, installing and configuring the right software to really 
     test its robustness and scalability.  If your developers (for
     whatever application you want to host on the back end of this
     LB cluster) has developed some load tests it will help immensely.
     However, it's been my experience that developing good load tests
     is more difficult than developing the core application.

     * Searching the LVS (Linux Virtual Server) site on "testing"
       seems to generate a number of interesting hits.  Read those.

     * Searching http://www.freshmeat.net on "load testing" generates
       about 25 hits and most of those are for web application load
       testing.

     * I've had minor experience with Frank Cohen's "Load" (formerly
       known as "TestMaker" or something like that:
            http://www.pushtotest.com/ptt

   * It's likely to take far more time developing a test harness
     than configuring LVS/IPVS (IPVS is the Linux kernel component of
     the LVS).  However, you might make a reasonable case to your
     management that such a test harness should include LVS as the
     baseline.  This might result in a decision to actually use LVS
     in production (if it surprises everyone by surpassing the
     competition, or if your management looks at the cost/benefit/risk
     analysis and decides based on that).

 If you do pursue this, please write up a report for all of us (or
 at least for me --- perhaps even for Heather as a Linux Gazette
 article).

-- 
Jim Dennis