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Date:      Thu, 12 Feb 2009 07:55:37 -0500
From:      Michael Powell <nightrecon@verizon.net>
To:        freebsd-questions@freebsd.org
Subject:   Re: Help with high LA
Message-ID:  <gn1678$9n0$1@ger.gmane.org>
References:  <alpine.BSF.2.00.0902121004300.98408@trex.centroin.com.br>

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scuba@centroin.com.br wrote:

> Hi All,
> 
> I need help for some strange problem with one of my servers, that can cost
> my job.
> 
> It's a FreeBSD 7.0-RELEASE-p5/amd64 running on a Dell PowerEdge III as a
> Virtual machine of VMware ESXi. There are only two VM in this box, and one
> of them (basicly a mail server) is running fine.
> 
> The problem is with high loads on the other one, that runs (besides other
> services) http and pop3.
> 
> TOP show LA from 40 to 90 most of the time.
> 
> I thought, at first, that was a disk botleneck due to some big mailboxes,
> or something related to some Apache (2.2.9) fine tuning, but it's
> something else.
> 
> 
> If I stop pop3 and apache services (the most active of the box), the LA
> drops to 1~2.
> Starting only one of them (any one) the LA rise to 20~40. Sugesting that
> it's not tied to a specific service.
> 
> I did a test running just pop3 (Qpopper), pointing the mail spool to a
> empty directory, to make shure that it's not a disk problem. And the LA
> also goes to sky (~30). The same happens with only apache running pointing
> to a simple http page.
> 
> The console shows messages like:
> 
> ipfw: install_state: Too many dynamic rules
> 
> I know I must review my rules and limit the number of keep-state entries,
> but a tryed to rise the number of dynamic buckets via sysctl:
> 
> sysctl -w net.inet.ip.fw.dyn_buckets=2048
> 
> But it seems it's not working, since the number of current buckets doesn't
> pass 256:
> 
> net.inet.ip.fw.curr_dyn_buckets: 256
> 
> I tryed to make some OS tuning, from the handbook, like increase the
> maxcon:
> 
> kern.ipc.somaxconn: 2048
> 
> but nothing seems to work.
> 
> Other entries in the logs:
> Feb 12 09:06:20 host1 inetd[1248]: accept (for ftp): Software caused
> connection abort
> Feb 12 09:06:20 host1 inetd[1248]: accept (for pop3): Software caused
> connection abort
> 
> I need some clues to undestand what is happening.
> 
> Thank you,
> 
>   - Marcelo

Me, I would get rid of inetd and just run the services as daemons. Since 
these are services which always need to be up there is no need for inetd. I 
also usually don't run firewalls on my service servers, but rather locate 
them in a subnet where there is a dedicated box for firewalling. I don't 
have the experience with your type of VM configuration, but I have the 
feeling that you could push the firewall function somewhere else. Dump inetd 
and if it is acceptable (e.g. you are behind something else) try running 
without ipfw.

You probably need to do some in depth profiling of your problem box, and I'm 
probably not at the level of expertise you need. There are others in the 
list which can be more helpful. Just thought I'd toss out what I'd look at 
first if it me. 

-Mike







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