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Re: [lvs-users] IPVS configurartion crashing down

To: "LinuxVirtualServer.org users mailing list." <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [lvs-users] IPVS configurartion crashing down
From: Joseph Mack NA3T <jmack@xxxxxxxx>
Date: Tue, 5 Jun 2007 18:02:58 -0700 (PDT)
On Wed, 6 Jun 2007, Kees Hoekzema wrote:

> However, today we changed the layout of our site, and it required us to
> install apache2 and php5 on the webservers next to apache1.3 and php4, which
> we require for some older software that isnt php5 compatible yet.
> We decided to let the apache 1.3 install have port 80, and give the apache2
> install port 81, before today the complete site was run on apache1.3.
>
> My ipvs config looks like this right now:
>
> IP Virtual Server version 1.2.1 (size=4096)
> Prot LocalAddress:Port Scheduler Flags
>  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
> TCP  213.239.154.36:80 wrr
>  -> 10.0.1.34:80                 Masq    32     0          422
>  -> 10.0.1.33:80                 Masq    55     2          1156
>  -> 10.0.1.36:80                 Masq    53     2          1222
>  -> 10.0.1.37:80                 Masq    57     0          1217
>  -> 10.0.1.38:80                 Masq    52     0          1167
> TCP  213.239.154.35:80 wrr
>  -> 10.0.1.34:81                 Masq    32     4          1664
>  -> 10.0.1.33:81                 Masq    55     8          4832
>  -> 10.0.1.36:81                 Masq    53     9          5118
>  -> 10.0.1.37:81                 Masq    57     3          5144
>  -> 10.0.1.38:81                 Masq    52     3          4928
>
> (weights are dynamicly changed every 10 seconds)
>
> Today we changed the port numbers for 213.239.154.35:80 to port 81 so our
> visitors went to the new site. However, this also increased the load on the
> loadbalancer dramaticly.

hmm. Julian (I thought) said that there was now no 
difference in speed between LVS-NAT and LVS-DR with the 2.4 
(and later kernels). However I don't remember asking him 
specifically about port translation. I assumed that was 
covered.

What if instead of changing the port number, you add another 
IP on each realserver, say 10.0.2.0/32 and have the apache2 
listen on port 80?

> At one point I had to stop each and every additional 
> service on the loadbalancer so it was only doing iptables 
> and ipvs, and still it was using up to 100% system-cpu 
> time. I noticed the InActConn on the .35 service was quite 
> high, when the site was doing 60 mbit I noticed over 
> 120.000 inactive connections. Can this be a problem?

the kernel will run out of resources. How far you need to go 
before that happens I don't know. The fact that the number 
is so different to the other machines probably means you've 
not configured that machine the same way (or something is 
different, NIC?)

Apache 1.x and 2.x are quite different as far as timings, 
keepalive time, number of demons... so it's no surprise that 
the InActConn is different.

> At the moment I'm using the 2.6.20.4 kernel - are there 
> any known bugs with it?

none, but it's a bit early to tell.

> P.s. The loadbalancers are Intel Celeron 2GHz w/ 512MB ram 
> boxes - which used to run the site perfectly fine for over 
> 4 years.

plenty of memory

Joe

-- 
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!


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