experiences with load balancers?
 

looking to hardware or software solutions that work for people.

i don't have a high loading.. need it more so for internally to route http API calls to multiple database servers for loading purposes (to increase throughput and scalability).

for software, i have found:

http://www.howtoforge.com/load_balan...proxy_balancer

http://www.inlab.de/balanceng/

http://haproxy.1wt.eu/

any experiences with these? looking for simple, easy to configure.

Fight the 411!

since you're looking for a database load balancer you could use
mysql-proxy + replication, works alright.

What kind of "routing" do you need?

Straight round robin?

Layer4 server affinity?

Layer 7 inspection?

Lots of options. If your load isn't nuts, haproxy is probably a good bet depending on your needs. If you want a more packaged solution, some of the hardware load balancers aren't bad depending on what you are looking for.

strictly HTTP. round robin can be the simplest method as long as it knows when a server goes down to stop routing to that server.

not looking for DNS round robin. wanting the balancer to balance between internal IPs so that I can have N number of database servers that receive http/php for api calls to the database, rather than direct db calls from my app.

so the webserver (ie. t3report.com) receives a user request for data. the server side makes http/api call to the rack (behind a firewall). the machine (ip) that it connects to is currently a server that then connects to the db to get the data.

in the new infrastructure, the webserver (t3report.com) makes http/api calls to the load balancer, from which it tunnels to the backend server, passing the http/api request, and data comes back.


Fight the unbalanced!

RRDNS is technically load distribution though, not balancing. If every connection is of generally invariable resource usage, then RRDNS will work perfectly.

If you need strictly HTTP proxying check out http://www.apsis.ch/pound/. I use it in production and it hasn't failed me.

Since all you need as round robin (or similar - idea being it doesn't matter which server a given connection ends up on), almost any load balancer will work.

For software, take a look a LVS or HAProxy - both will do what you want. If your needs are even simpler, you could even look at nginx, or varnish if you wanted to consider caching.

For devices - honestly at low traffic levels anything will work. I'm not too well versed on the lower end of the spectrum here, but in the mid-range the Foundry ServerIrons tend to be the best performance for the dollar (however, they are not exactly fun to configure).

I think the decision on what to use is if you can live with a single point of failure in your load balancer or not. If not, the devices may be easier to setup auto failover with.

-Phil

if you're looking for traffic under 100mbit, you can find the foundry load balancer switch on ebay for fairly cheap. the foundry serveriron XL FCSLB ( 8 or 16 ) the 8 or 16 mean how many ports there are. The setup is not that bad. the serveriron comes with a small gui you can use to configure the load balancer.

If you're looking for free opensource stuff, check out the already mentioned items above and this place


http://www.ultramonkey.org/
uses LVS and HA

Good luck

i'll be looking into load balancing this weekend, great thread. i'll post anything else i may turn up too.

many thanks for the great replies.. i am looking into "pound" from sansa's post.

I'll post up my results as well once I am done evaluating the various solutions.

Fight the QA!

I have experience with load balancers from Cisco and Big IP... and have read some on the ServerIron product. They're dang good at what they do, but probably overkill.

I have also used the Fortinet appliances to load balance. Even their smallest sub-$1k box can do this. Bonus is they are also a firewall, do AV, intrusion detection/prevention, spam control, etc.

If you're interested in Fortinet, hit me up ... I'm a dealer! :D