Hi.
I know next to nothing about load balancing per se, so this will be a
very naive question related to the data below : does it matter ?
I mean, I can see that the load appears to be uneven, but the grand
total seems to be about 10% of the available cpu time.
So do you really care if one instance is using 4% and another 0.4% if
there is still 90% available in total ?
I am also wondering if what is shown down there is not just this
phenomenon : whenever the load balancer has to decide to which back-end
to pass a request, I suppose it checks first which ones are already
busy. Since in this case the total load is light and most of them are
always free, it might just take the first of the list, which then ends
up more used than the others. No ?
André
fernando castano wrote:
> Hi all,
>
> I'm new to apache. I am experiencing a problem with apache load
> balancer. I configured the load balancer across 10 app servers
> (glassfish domains), but when I see the way the cookies (and load) are
> distributed I see a very uneven distribution. Here is my proxy
> configuration:
>
>
> fc112959@(protected)
> # configuration for clustering more then one glassfish
> ProxyPass / balancer://cluster/ stickysession=JSESSIONID nofailover=Off
> ProxyPassReverse / http://kenstgapp01:8080
> ProxyPassReverse / http://kenstgapp01:8280
> ProxyPassReverse / http://kenstgapp01:8380
> ProxyPassReverse / http://kenstgapp01:8480
> ProxyPassReverse / http://kenstgapp01:8580
> ProxyPassReverse / http://kenstgapp01:8780
> ProxyPassReverse / http://kenstgapp01:8880
> ProxyPassReverse / http://kenstgapp01:8980
> ProxyPassReverse / http://kenstgapp01:9080
> ProxyPassReverse / http://kenstgapp01:9180
> <Proxy balancer://cluster/ >
> BalancerMember http://kenstgapp01:8080 route=kenstgapp01_8080
> loadfactor=1
> BalancerMember http://kenstgapp01:8280 route=kenstgapp01_8280
> loadfactor=1
> BalancerMember http://kenstgapp01:8380 route=kenstgapp01_8380
> loadfactor=1
> BalancerMember http://kenstgapp01:8480 route=kenstgapp01_8480
> loadfactor=1
> BalancerMember http://kenstgapp01:8580 route=kenstgapp01_8580
> loadfactor=1
> BalancerMember http://kenstgapp01:8780 route=kenstgapp01_8780
> loadfactor=1
> BalancerMember http://kenstgapp01:8880 route=kenstgapp01_8880
> loadfactor=1
> BalancerMember http://kenstgapp01:8980 route=kenstgapp01_8980
> loadfactor=1
> BalancerMember http://kenstgapp01:9080 route=kenstgapp01_9080
> loadfactor=1
> BalancerMember http://kenstgapp01:9180 route=kenstgapp01_9180
> loadfactor=1
> </Proxy>
> fc112959@(protected)$
>
> And here is how the load gets distributed across jmeter 10 clients: as
> you can see, only 7 of the jvms get work, and among them the amount of
> work they do is very uneven (second to last entry in each row is % of
> cpu used by the process).
> These domains are exactly the same. I've checked the cookie
> distribution and reflects the load distribution (uneven). If I increase
> clients I eventually get work in all jvms (still uneven), and that just
> proves that all jvms can be routed thru apache load balancer. I am
> generating load with jmeter. Any hints of what am I doing wrong? how to
> fix it?
>
>
> PID USERNAME SIZE RSS STATE PRI NICE TIME CPU
> PROCESS/NLWP 1388 root 3338M 3257M sleep 0 0 9:08:45
> 6.5% java/89
> 1414 root 3332M 3253M cpu28 0 0 7:32:01 4.2% java/92
> 1417 root 3333M 3253M cpu9 0 0 7:14:39 2.3% java/96
> 1424 root 3332M 3254M cpu12 0 0 7:03:12 2.2% java/89
> 1420 root 3332M 3254M cpu6 0 0 7:35:40 2.1% java/89
> 1411 root 3333M 3253M cpu29 0 0 7:31:31 1.9% java/87
> 3461 webservd 40M 32M sleep 0 0 0:00:03 0.3% httpd/1
> 3460 webservd 36M 26M sleep 0 0 0:00:03 0.3% httpd/1
> 3462 webservd 36M 26M sleep 0 0 0:00:03 0.3% httpd/1
> 3457 webservd 32M 27M cpu24 0 0 0:00:02 0.3% httpd/1
> 1423 root 3333M 3256M sleep 0 0 7:00:01 0.2% java/88
> 3348 webservd 40M 32M sleep 0 0 0:00:04 0.2% httpd/1
> 995 root 3536K 3072K sleep 100 - 0:00:46 0.1% cpustat/33
> 1360 webservd 43M 35M sleep 0 0 0:00:14 0.1% httpd/1
> 1337 webservd 43M 35M sleep 0 0 0:00:13 0.1% httpd/1
> 3559 webservd 13M 11M cpu20 0 0 0:00:00 0.1% hgwebdir.cgi/1
> 883 root 3848K 3832K cpu25 0 0 0:00:13 0.1% prstat/1
> 1011 webservd 43M 36M sleep 0 0 0:00:15 0.1% httpd/1
> 77 webservd 9016K 7832K sleep 0 0 0:16:18 0.1% memcached/1
> Total: 166 processes, 1525 lwps, load averages: 10.00, 10.20, 10.03
>
> TIA,
> fdo
>
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