very little difference. there is, but not all that much more noticeable. this is why i'm very confused with how to test the load balancer.
If I do the EXACT same test I preform on the WS1, onto the LB, then it should be the same, plus a bit for "another hop" and this is what I get.. so this is fine. now this is with 300 users. so, if I have 2 x WS, WS1 and WS2, identical machines, returning identical results, then in THEORY, I should be able to send 600 users to the LB, that will evenly send them out to WS1 and WS2, which I have done in the config. I even confirm that there are the same amount of connections for each WS: watch ipvsadm --list --stats and well the results, SHOULD be the same latency + 1 hop worth of latency as a single WS, right? I don't.. I get 2x the latency, OR, the same latency as I would if I sent 600 users to a single WS... SO, since this is the case, I want to rule out the LB, and in order to do that, I have to do a test, that would simulate the LB with my JMETER. So the question is how do I do that? I thought, logically I would do 600 users, but that produces the same results as sending 600 users to only 1 of the WS... so I'm a bit confused, and so I thought I'd ask someone if they have done a test like this, and what's the best way to approach.. thanks for your time! Will On Sun, Jul 4, 2010 at 2:23 PM, Sudip Kumar Bhattacharya < [email protected]> wrote: > Check your web server logs to verify that the loads are getting equally > distributed between the 2 servers. > Also the diff between the 2 modes is that first u had direct access to the > 2 servers, but now u r going thu an extra hop on the LB. > This extra hop will also add to the latency. > Try this. Target ws1 directly with 600 hits, and target ws1 again with 600 > hits but this time thru the lb. See how much latency the lb adds. > Sent on my BlackBerry® from Vodafone > > -----Original Message----- > From: William Ottley <[email protected]> > Date: Sun, 4 Jul 2010 14:16:53 > To: JMeter Users List<[email protected]> > Reply-To: "JMeter Users List" <[email protected]> > Subject: Re: simulate test as a LB, with 2 webservers at one time > > Your right. > When I test the LB: 600 users, with 3 httpdclient urls. > I test this to see if I get "close" to the same latency, as 2 web > servers getting 300 users each with 3 httpdclient urls. > > I don't. I get 2x the latency, or the same latency as when I send 600 > users with 3 urls to 1 webserver. > > So I'm trying to find where the problem is. > > Sent from my iPhone > > On 2010-07-04, at 1:57 PM, "Sudip Kumar Bhattacharya" < > [email protected] > > wrote: > > > If you are using a load balancer it wud normally front end on all > > requests. > > You wud not have to generate different urls on jmeter to reach > > different servers as your mail suggests. > > Having said that. Load balancers also have stickiness rules which > > send consecutive requests from the same session or same ip to the > > same web server for maintaining session data continuity. > > You may not get an equally distributed load balancing between the > > two servers. > > Chen out your particular LB algorithm setting to get a better idea. > > Sent on my BlackBerry® from Vodafone > > > > -----Original Message----- > > From: William Ottley <[email protected]> > > Date: Sun, 4 Jul 2010 13:47:59 > > To: <[email protected]> > > Reply-To: "JMeter Users List" <[email protected]> > > Subject: simulate test as a LB, with 2 webservers at one time > > > > Hi all, > > > > I'm trying to solve an issue with regards to latency and Load > > Balancing. > > > > I have done several latency tests using jmeter. > > I have tested each of the webservers with this: > > > > 300 threads, and 3x HHTP Request HTTPClient, each one has a > > different url > > location. > > > > If I wanted to get the results of a Load Balancer, serving the 2 > > webservers, > > would I: > > > > a) do 600 threads, and 3x HHTP Request HTTPClient, each one has a > > different > > url location (for webserver 1) and 3x HTTP Request HTTPClient (for > > webserver > > 2) > > or > > b) do 300 threads and 6x HTTP Request HTTPClient, done so that the > > first one > > is with WS1, first url, 2nd one is WS2, first url, etc.... > > > > in my head, logically, a LB, should be able to sever 600 clients, > > with 3 > > HTTPClient requests: while having almost the same latency.. but i'm > > not > > getting that. > > > > > > so I decided to use jmeter to simulate conecting to both webservers > > at the > > same time... > > > > I hope this makes sense.... > > > > > > thanks! > > > > William > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] > >
