Re: pen and high loads

From: Sean Cross (
Date: Mon Jun 24 2002 - 23:18:21 CEST

Right now, I am running Pen 0.9.0 on our website which gets steady traffic of
1.5-2mb/minute distributed over 2 servers. Right now, it has about 450
simultaneous connections. (The limit is 507 currently. I will be very happy
when full poll() support is added.)

It is running on port 80 and port 443, hashed, which increases the amount of
power being used.

The computer is a Celeron 1.0 Gigahertz, and has 128 megs of memory. It is
running the lastest rsync'ed version of Gentoo. Pen is the only major
program running (aside from various logging facilities, GPM, and a monitoring

I suspect we may be under the occasional attack by various [D]DOSes, but I
really haven't seen anything major.

Right now, Pen is using 35% of the CPU. The queue length is hovering around

Overall, I am very pleased with its performance.

What you might want to do is run a program such as "top", to figure out what
the top usage of CPU is. As I said, Pen is at the top on my particular

It may also be disk throughput. Your swap may have been 100% free, but it may
have cached various things to the disk.

If you're feeling particularly clever/bored/whatever, one interesting trick
may be to use a flavor of linux that comes on a single floppy (such as a
version of LRP, or muLinux) and run it without even touching the hard disk.
If it works fine, then you know it's disk related.

On Monday 24 June 2002 01:16 pm, Joćo Paulo Vasconcellos wrote:
> Hello,
> I run a web site with an average load, that in special dates get a boost
> in traffic. We have 3 web servers load balanced by pen, and in Valentine's
> Day, my site got very slow. I tried to access each web server directly,
> instead of going thru the load balance and I got the pages very fast (
> about 20 sec. ), while the same pages thru the load balance got 1 ~ 2
> minutes to download. I was having 300 ~ 400 simultaneous connections,
> according to pen, while the limit I set was of 2048 clients. Anybody knows
> if pen does not handle well more than 200 connections at a time, or if it
> is something concerning the OS ?
> I run pen in a celeron 500, with 32MB RAM with Debian potato and compiled
> pen with gcc 2.95.2.
> The bottleneck wasn't RAM, because I got 4~8 MB of Free RAM, and my swap
> was 100% free.
> Thanks in advance,

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