Sent on my BlackBerry® from Vodafone -----Original Message----- From: "Sudip Kumar Bhattacharya" <[email protected]> Date: Sun, 4 Jul 2010 18:49:11 To: William Ottley<[email protected]> Reply-To: [email protected] Subject: Re: simulate test as a LB, with 2 webservers at one time
Create 2 threadgroups in ur test. Point 300 users in tg1 to ws1, and similarly for the other tg2 to ws2. Each tg wud run parallelly. Run this without the lb. You maybe getting choked on the lb. Some lbs do a real time health check on ws to decide how to distribute the load. That may add to the latency as well. Sent on my BlackBerry® from Vodafone -----Original Message----- From: William Ottley <[email protected]> Date: Sun, 4 Jul 2010 14:41:52 To: JMeter Users List<[email protected]>; <[email protected]> Subject: Re: simulate test as a LB, with 2 webservers at one time 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] > >
