[Linux-cluster] Trying to locate the bottleneck

[Jeff Sturm]

Hi Raymond,

At those concurrency levels I would suspect network tuning may help.
Does dmesg show anything interesting on the load balancers during your
testing?

For high levels of concurrency on a NAT'd firewall or load balancer I
specifically remember having to adjust ip_conntrack_max upwards.
Perhaps network buffers as well.

-Jeff

> -----Original Message-----
> From: linux-cluster-bounces at redhat.com
[mailto:linux-cluster-bounces at redhat.com]
> On Behalf Of Raymond Setchfield
> Sent: Tuesday, July 07, 2009 8:35 AM
> To: linux-cluster at redhat.com
> Subject: [Linux-cluster] Trying to locate the bottleneck
> 
> Hi
> 
> I am trying to find a problem here with a setup which I am currently
> testing.
> 
> This is the current setup which I have at the moment
> 
> 15 web farm servers which are running vhost-ldap module and also have
> ldap caching enabled. Which are behind 2 Load balancer servers which
are
> in fail over. The software which it is currently running is Piranha on
> the load balancers.
> 
> I am using siege to get some benchmarking done on these to test
> basically their availability when pushing high concurrency.
> 
> At 100 (99.60 according to siege) Concurrent Connection it appears to
be
> all ok with 99.89%. At 120 (119.52 according to siege) Concurrent
> connections I get 99.9%, and at 130 (129.51 according to siege)
> Concurrent Connections I get 100% availability.
> 
> However pushing it any further than this, for example 150 concurrent
> connections it is falling over and siege bails out with multiple
> connection time outs. I am trying to find the bottle neck here and I
am
> wondering if it is software which I am using for the load balancers or
a
> limitation with apache.
> 
> The command I am using for siege is pretty simple nothing special;
> 
> siege --concurrent=150 --internet --file=urls.txt --benchmark
--time=60M
> 
> My lvs.cf file can be found here to show you guys the config which I
am
> using.
> 
> http://pastebin.com/m52d6cc23
> 
> Any help would be greatly appreciated
> 
> Many Thanks
> 
> R.
> 
> --
> Linux-cluster mailing list
> Linux-cluster at redhat.com
> https://www.redhat.com/mailman/listinfo/linux-cluster