jaymc Posted January 6, 2009 Share Posted January 6, 2009 I have 7 web servers 1 of them acts solely as a loadbalancer The other 6 are node web servers, in other words if 4 go down I still have 2 serving my website Each node web server is set to handle 150 max connections, so 900 in total between all 6 webservers Lets just say I had 800 connections at one time, they all have to pass through the loadbalancer which means that one server is dealing with 800 connections Im worried it will cripple the loadbalancer Here are my questions 1: Because mod_proxy just forwards the request and doesnt actually process it, should I have peace of mind 2: If max clients on the load balancer hits 150, does that mean regardless of having 6 nodes each handling 150, will requests que? Quote Link to comment Share on other sites More sharing options...
corbin Posted January 7, 2009 Share Posted January 7, 2009 In that situation, the load balancing server would be the bottle neck. The load balancing server needs to be able to handle the same amount of connections as all of the other servers combined. When I think about it, I don't know if mod_proxy is that good of setup for a load balancer x.x. Quote Link to comment Share on other sites More sharing options...
jaymc Posted January 7, 2009 Author Share Posted January 7, 2009 But surely as the apache loadbalancer is just forwarding requests, it wont be under that much strain? Quote Link to comment Share on other sites More sharing options...
tomfmason Posted January 7, 2009 Share Posted January 7, 2009 I think handling this on the DNS level would better. With a round robin setup you could have 8 apache servers instead of 7 and not have to worry about the apache load balancer. Quote Link to comment Share on other sites More sharing options...
corbin Posted January 8, 2009 Share Posted January 8, 2009 But surely as the apache loadbalancer is just forwarding requests, it wont be under that much strain? Eh, yeah, but you still have the over head of Apache and mod_proxy. I just think something better has to be out there. I personally like Tom's suggestion of doing it on a DNS level. Other than that, I think something that simply passed on connections would be better. I might run some benchmarks later on mod_proxy if I get bored. Somehow passing traffic through mod_proxy to other servers seems like it would be... problematic. Just of curiosity, how are you deciding which server to pass the traffic to? Quote Link to comment Share on other sites More sharing options...
tomfmason Posted January 8, 2009 Share Posted January 8, 2009 You should also make sure that each of the servers are optimized as much as possible. Devside has a nice overview of apache performance tuning. Another thing to consider is moving all static files to a single server. The main reason for that is that there are optimizations for dynamic content that could adversely affect performance for certain types of media and vice versa. I am doing something very similar to this for a client now but we are using Amazon S3 for the static/media files. Quote Link to comment Share on other sites More sharing options...
jaymc Posted January 8, 2009 Author Share Posted January 8, 2009 DNS is no good as if a server dies a percentage of clients can not get onto my site Loadbalancing helps distrobute the load and has fail over where as if a server dies it is automatically taken out of the loop mod_proxy can also target servers that are not under as much load. It makes sense And yes, I also have lighttpd running on each of the web servers that deal with static images/files. Each server has 5GB of ram and sessions are handled in memcached etc. Its pretty nice It would be great for feedback on mod_proxy, I would be suprised if thats the bottle kneck based on its just forwarding requests as apposed to actually processing. I have loads of CPU and RAM to throw at it Quote Link to comment Share on other sites More sharing options...
steviewdr Posted January 8, 2009 Share Posted January 8, 2009 Here is a nice presentation regarding load balancing etc. http://www.spoofedpacket.net/files/docs/ftpdot-ilug-20081213.pdf -steve Quote Link to comment Share on other sites More sharing options...
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