Thomas Nayler

Thomas Nayler is a London based jeweller specialising in custom graffiti style pieces . Quite resonably priced he has supplied commisions to the stars and been featured in many lifestyle magazines. I decided to get another piece of his work commissioned lately and here are the results.



The first piece I had made I haven't take off since I bought it and often gets commented on.



You can get your own and browse his work here Thomas Nayler

DreamBox DM600PVR

So after years of ignoring the compact pc I purchased to install MythTV on to use as a personal video recorded with added bonuses like network connectivity and ability to add modules to increase functionality I decided to leave it tasked as a email/web server and invest in a shiny new DreamBox. I have only seen dreamboxes in Egypt and most of those quite old models so I had a look to see what was on offer and found a number of interesting units. The daddy of them all the dm8000 has dual tuner internal hdd support and hd support but wasn't out yet so I turned my eyes to the dm800 its smaller brother who has the same features but with one tuner but sadly still a big price tag for someone like me who doesnt have a HD tv and isn't that interested in owning one in the near future. The next in the lineup to me seemed to be the new dm600pvr although often ignored due to lack of dual tuner like the 702x range it's small size and reasonable price made it very attractive to me.

The dreambox was simple to setup out of the box and occupied the same space under my tv that my sky digibox had done plus an extra cable to give an internet connection via my sky netgear router. Upon scanning for channels I realised I had an issue as by default it doesn't have any softcams which emulate provider encryption services so you can't use your sky card or someone else sky card id(not currently possible for NDS the system sky uses but possible for other providers) or share their sky card over the internet for example to decrypt the channels you usually get and some you don't usually get. I chose to go with the softcam CCcam but the Enigma image that comes on the dm600pvr is a little fiddly to add software and manage softcams with and turns it more into linux sysadmin work so to allow everyone in the house to have a play I replace it with the latest Gemini image which was 4.40.

Upgrading the image wasn't the simplest of process not having windows to hand or a working serial port and hearing tales of woe from people trying to use usb->serial cables I googled and found that if you fix your dreambox IP address on your DHCP server so it's now static then telnet to it and type the following:

mount /boot -o remount,rw
rm /boot/*
reboot

Once rebooted if you hit the web interface it gives you an option to re flash the unit with the image of your choice!

Now Its just a matter of using the blue menu / addons and download CCcam and a config file for it then select CCcam in the blue menu. Sky cards now work in the front slow and you have the ability to download the latest keys from satanddream ready for manual install in Gemini which is a user contributed source of keys for opening up more channels. There is much more you can install or addon but I recommend MultiView or MV for EPG which you can feed using xmltv project and their radio times script.

Man Page Bugs

Just noticed CentOS5 has a man page bug and may not be the only disto to have it as when I google for the same man page I get similar results.

Compare man mkfs.ext3 to http://man-wiki.net/index.php/8:mkfs.ext3

You will notice the following is missing:

-I inode-size

Specify the inode size. The default inode-size used by mke2fs is 128. inode-size can be 128, 256, 512 or

1024. This value generally shouldn't be changed!

It almost led me to recreate a filesystem with the wrong option as I did not believe GlusterFS docs would be more complete than my current distros.

RedHat Installer aka Anaconda

What an annoying inflexible tool! It reminds me of Windows in it's methodology e.g. abstract everything from the user so that he doesn't have to know anything, hide real problems from the user so he doesn't know whats broken and then won't worry, stop the user from being able to manually setup anything so he can never fix any problems that occur from the automated fashion the installer uses. What happened to the rescue shell that used to start back in the day giving you some flexibility? What happened to the option of loading another driver at install time from supplemental CD/DVD or the Internet? What happened to the ability to partition using fdisk or something seperate from the anaconda script?

IMHO all this type of thing breeds is a new type of Linux admin very similar to a Windows admin of late who can only follow others step by step work and heavily reliant on Wizards and management GUIs while pissing off the experience Open Source community members who are forced to use distributions like these because of their support structure and market share.

Dell Hell

Had to contact Dell today for some assitance with their new PowerEdge 2950 servers we have just bought. We planned to run raid6 on all 6 drives and use that both for the OS and storage.

Seemed like a good plan till I realised partitions => 2GB are not supported without efi support but more importantly grub and lilo can't boot EFI/GPT configured drives.

There however is a workaround for this in the form of a linux kernel driver for EPI support to access those big partitions called efivars and a boot manager called efibootmgr which seems like a modified version of lilo.

The kernel module required seems to be included with the currently linux kernel in RH/Centos 5.1 but the efibootmgr http://linux.dell.com/efibootmgr/ needs to be installed and the disk partioned with an EFI partition for boot at the start of the disk as outlined in http://www.centos.org/docs/5/html/Installation_Guide-en-US/s1-diskpartitioning-x86.html.

Seems simple enough but as an admin used to fdisk I could not achieve this in DiskDruid without some further instruction.

On calling Dell support I was told that support can not be given as I'm not using thier OEM RH 5.1 CD and rather a downloaded version without their branding which would have no effect on issues I could face yet they still leave me unsupported!! After explaining for 10 minutes the situation did not change, and asking to speak to a supervisor resulted in the original operator rejoining the conversation to re iterate how Dell support will not help to resolve this issue and ending the conversation in a manner that led me to believe that was the last I'd hear from Dell.

However, today just as I had finished cussing Dell support I had a phonecall from a knowledgable chap with an Irish accent who talked me through possible options and one I was not aware of before. Raid on the raid controller supplied with the PE 2950 can be configured to create virtual disks on the raid arrays and unlike I had guessed you can have more than one of these per raid array so it's possible to create a small virtual disk that grub/lilo can boot and still use one raid6 array so no space is wasted :)

Just wanted to add the first support op who I spoke to called me back yesterday to confirm my resolution was successful. I'm still not clear if I miss understood the original operator and I was to be helped he just wasn't positive I'd get the support I needed as other customers haven't had success or if my call was listened to and a different action to the usual decided on since I presented myself as a very influential client.

Stolen Laptop data Recovery Script

I was bored last night and got inspired by the post
here about someone having a laptop stolen and created a script to recover data from a stolen laptop and alert me of it's current IP.

#!/usr/local/bin/bash
# Description: Stolen Laptop data Recovery Script (untested)
# Author: alistar@phrostbyte.dhis.org
# Date: 2008/07/10 21:16 BST
# Usage: Copy to /usr/local/bin/stolen.sh and crontab with the following:
#        */10 * * * * /usr/local/bin/stolen.sh >/dev/null 2>&1
# Requirements: You must have wget, tcping nc installed and in the crontab users path
#
# Variables:
# Your home directory you want backed up. Remember the crontab user must have read rights to this directory.
home="/home/alistar"
# The host you want to backup your data too and are able to run nc exposed to the internet on.
backuphost="phrostbyte.dhis.org"
# The file you need to create to enable the recovery script.  Just echo 1 to this.
stolenfile="http://phrostbyte.dhis.org/~alistar/stolen.html"
# Your email address.  I personally use one that SMSs my phone or set a rule to SMS me on my mail server
email="alistar@phrostbyte.dhis.org"
# The mails themselves.  You may customise these if you so wish
subject='Your STOLEN Laptop is Online!'
ip=`wget -q http://www.biomedcentral.com/whatsmyip.asp -o /dev/null -O - | grep '<b>' | cut -d '>' -f3 | cut -d '<' -f1`
body="
Your stolen laptop is now online at $ip\n
\n
Please logon to $backuphost and run 'nc -k -l 31337 > home.tar.bz2'\n
\n
"
subject1='Your STOLEN Laptop Backup is now Complete!'
body1="
You may now remove $stolenfile and quit your 'nc -l 31337 > home.tar.bz2 command'\n
\n
"
###
echo -e $body > /var/tmp/body.txt
whois $ip >> /var/tmp/body.txt
echo -e $body1 > /var/tmp/body1.txt
wget -q $stolenfile -O /dev/null
if [ $? -eq 0 ]
then
  if [ -f /var/tmp/myip ]
  then
    myip=`cat /var/tmp/myip`
  else
    myip="0"
  fi
  if [ $ip != $myip ]
  then
    mail -s "$subject" $email < /var/tmp/body.txt
    echo $ip > /var/tmp/myip
  fi
  tcping $backuphost 31337
  if [ $? -eq 0 ]
  then
    ps -ax| grep "nc $backuphost 31337" | grep -v grep
    if [ $? -eq 1 ]
    then
      if [ ! -f /var/tmp/backupcomplete ]
      then
        tar -cjvf - $home | nc $backuphost 31337
        if [ $? -eq 0 ]
        then
          mail -s "$subject1" $email < /var/tmp/body1.txt
          echo 1 > /var/tmp/backupcomplete
        fi
      fi
    fi
  fi
else
  if [ -f /var/tmp/backupcomplete ]
  then
    rm /var/tmp/backupcomplete
  fi
  if [ -f /var/tmp/myip ]
  then
    rm /var/tmp/myip
  fi
  if [ -f /var/tmp/body.txt ]
  then
    rm /var/tmp/body.txt
  fi
  if [ -f /var/tmp/body1.txt ]
  then
    rm /var/tmp/body1.txt
  fi
fi

CentOS 5 GFS Install

I have decided to include the steps I felt I needed to take to make a test install of GFS before I decided not to use it. It doesn't cover clvm configuration but it's very similar to LVM2 which is well documented on the net so I decided not to include it here.

#NTP is needed on every node in the cluster sync'd to the same place of course
yum -y install ntp
#Needed for gfs clustering
yum -y groupinstall Clustering
#GFS kernel module and FS utils
yum -y install gfs-kmod
yum -y install gfs-utils

#Needed to get the stupid system-config-cluster running for configuration of the cluster
yum -y install xorg-x11-xauth xorg-x11-fonts-base xorg-x11-fonts-Type1

#NTP is needed on every node in the cluster sync'd to the same place of course
chkconfig ntpd on
service ntpd start

#Stop updatedb trawling our gfs mounts
echo 'PRUNEFS = "auto afs iso9660 sfs udf"
PRUNEPATHS = "/afs /media /net /sfs /tmp /udev /var/spool/cups /var/spool/squid /var/tmp /cvp /mnt/cvp /media"' > /etc/updatedb.conf

# Create the filesystem with 125 journals(nodes) clustername coull and fs name cvp on /dev/hdb
gfs_mkfs -p lock_dlm -t coull:cvp -j 125 /dev/hdb

#config /etc/cluster/cluster.conf using system-config-cluster by throwing the x connection back to your machine via SSH

#add cluster hosts to /etc/hosts not DNS as this introduces a point of failure and some slowdown.

#Start clustering and GFS services
service cman start
service clvmd start
service gfs start

#Mount SAN device which should be a clv (centralised logical volume)
mount -t gfs /dev/san1/lvol0 /san -o noatime

# Memcache anyone?  Not sure what the options are for yet as I've never set it up before
/usr/bin/memcached -d -m 512 -l 192.168.2.100 -p 11211 -u nobody