Karl has been volunteering in PNG for couple weeks now to help setup 120 odd PC’s in local hospital in Goroka that ITShare have donated to them. All the computer have Linux installed on them and Karl is over there to help setup the network and servers etc for the hospital. There is some pictures up on the web of how things are going over there with the unloading of the 40 foot shipping container couple days ago that left Adelaide for Goroka a couple months ago, and the setup of some the computers and Karl teaching a couple the locals.
Below is a snippet of what was forwarded to me via email from a friend, that was originally emailed out in the Builder AU newsletter on July 26th 2007. Hope people find it useful as I have, I have only tested the information below on a test box and was happy on the increase of throughput from that box. When i get a chance I’ll try to add couple before and after screenshots
The Linux kernel and the distributions that package it typically
provide very conservative defaults to certain network settings that
affect networking parameters. These settings can be tuned via the /proc
filesystem or using the sysctl program. The latter is often better, as
it reads the contents of /etc/sysctl.conf, which allows you to keep
settings across reboots.
The following is a snippet from /etc/sysctl.conf that may improve
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_syncookies = 1
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.ipv4.tcp_rmem = 4096 87380 16777216
net.ipv4.tcp_wmem = 4096 65536 16777216
The above isn’t to replace what may already exist in /etc/sysctl.conf,
but rather to supplement it. The first command enables TCP window
scaling, which allows clients to download data at a higher rate by
enabling extra bits in TCP packets that are used to increase the window
The second command enables TCP SYN cookies, which is often enabled by
default and is extremely effective in preventing conditions such as SYN
floods that can drain the server of resources used to process incoming
The last four options increase the TCP send and receive buffers, which
allow an application to move its data out faster so as to serve other
requests. This also improves the client’s ability to send data to the
server when it gets busy.
By adding these commands to the /etc/sysctl.conf file, you ensure they
take effect on every reboot. To enable them immediately without a
# sysctl -p /etc/sysctl.conf
To see all of the currently configured sysctl options, use:
# sysctl -a
This will list all of the configuration keys and their current values.
The sysctl.conf file allows you to configure and save new defaults;
what you see from this output are the defaults defined in the kernel
that are currently effective. To see the value of one particular item,
# sysctl -q net.ipv4.tcp_window_scaling
Likewise, to set the value of one item without configuring it in
sysctl.conf — and understanding that it won’t be retained across
# sysctl -w net.ipv4.tcp_window_scaling=1
This can be useful for testing the effectiveness of certain settings
without committing them to being defaults.
Well today has been an interesting day working on my new server that I got last Wednesday. My new server is a Compaq Proliant ML530 in a 7U 19″ rack mountable. I know it an old server and weighs heaps and needs 2 people to move it, but it a starter to help make things little more professional for the web sites i host.
Well the interesting problem i was having is that when i installed Debian 4.0r0 (Etch) it was only seeing one of the CPUs. So after playing around with different boot options as Debian boots up it was still not seeing the second CPU. So I went and had a look around the HP/Compaq web site about my server to see what they had to say and see if i could find the software needed to access the BIOS, well after bit of searching i found the Software / Drivers page for my server and saw there was a SmartStart Software CD to download. While the CD was trickling down from there server I went off and done couple other things to kill the time.
By now it has been a couple hours waiting for the download to finish, but i have a hot off the burner a freshly burnt CD of the HP SmartStart Software, now it time to boot the server up off the CD. While the server was booting up off the CD I thought it was time for a coffee, well when i got back it was sitting there with a error on the screen about not having a mouse attached and the GUI stuff would not allow me to tab around and select what i wanted. Ok ended up having to look for a ps2 mouse to plug into it and do a reboot.
Now I got a mouse plugged in and the system rebooted. Time to get into the BIOS and see what is going on there, when i got into the BIOS i noticed one thing straight out was about the OS and that was set to other so I highlighted it and pressed enter to see what other options it had to offer and noticed that there was an option for UNIX and when i selected that it gave some more options and the last option there was Linux so I selected it which then changed and interrupt from 5 to 10. I finished off looking through the BIOS to see if there was anything else that might need to be change, which there wasn’t. So after saving the BIOS and exiting out the SmartStart Software and rebooting the server, I logged in and typed cat /proc/cpuinfo and low and behold there was my second CPU finally being recognized, so me does the happy happy joy joy dance.
Welcome to my Blog. This is my first post. I will get more happening soon here