So, I asked the VMWare admin to add an extra virtual disk for me on each of those machines. and I extended (/) partition to the new disk.

Keeping in mind to follow the procedure is: /dev/sda was the only disk for each machine. So, when we added an extra disk, it was assigned /dev/sdb

Using fdisk, create a new partition:

fdisk /dev/sdb

Make sure you make your choices as primary and assign it first partition.

So, once created, it shall be assigned /dev/sdb1

pvcreate /dev/sdb1

This will create a physical volume for the LVM.

And after creating the physical volume we attach it to our existing Volume Group.

vgextend VolGroup00 /dev/sdb1

Then we extend the Logical Volume which is mounted to (/) by 20GB, make sure you change the number to the attached disk storage.

lvextend -L +20G /dev/VolGroup00/LogVol00

Then we resize the filesystem, since we are running default installs, it runs ext3, so extending it online using the command below:

resize2fs /dev/VolGroup00/LogVol00

Verify the new storage size using:

df -h

It must show the extra 20GB or whatever disk size you added.

perl -e “s/text/replacewith/g;” -pi.orig *.txt

This is going to save a backup of the files with .orig extension and do the replace. If you don’t want backup, then remove the .orig from the line.

Also, if you want to replace text in all files in a directory, then use:

perl -e “s/text/replacewith/g;” -pi.orig $(find . -type f)

So, I thought of sharing my /etc/odbc.ini and /etc/odbcinst.ini since I had a bit of hard time writing them. It may help someone who is trying to figure out how to connect using ODBC on Linux.

Packages Required on CentOS

httpd php unixODBC

Manually Install Oracle Instant Client 11.1 RPM Packages and Install Sybase ASE from the TGZ File.

For Oracle you need to copy all the libs to /usr/lib

cp /usr/lib/oracle/11.1/client/lib /usr/lib/

/etc/odbcinst.ini Contents:

[Oracle]
Description     = Oracle ODBC Connection
Driver          = /usr/lib/oracle/11.1/client/lib/libsqora.so.11.1
Setup           =
FileUsage =
CPTimeout =
CPReuse         =

[Sybase]
Description = Sybase ODBC Driver
Driver = /opt/sybase/DataAccess/ODBC/lib/libsybdrvodb.so
FileUsage = -1

/etc/odbc.ini Contents:

[Oracle]
Application Attributes = T
Attributes = W
BatchAutocommitMode = IfAllSuccessful
CloseCursor = F
DisableDPM = F
DisableMTS = T
Driver = Oracle
EXECSchemaOpt =
EXECSyntax = T
Failover = T
FailoverDelay = 10
FailoverRetryCount = 10
FetchBufferSize = 64000
ForceWCHAR = F
Lobs = T
Longs = T
MetadataIdDefault = F
QueryTimeout = T
ResultSets = T
ServerName = //serverip:port/dbname
SQLGetData extensions = F
Translation DLL =
Translation Option = 0
UserID =

[Sybase]
Driver = Sybase
Server = serverip
Port = serverport
Database = dbname

PHP Script to Test ODBC Connectivity:

<?php

$query = “select * from table_name”;

$conn = odbc_pconnect(“DSN”, “username”, “password”);

if(!$conn) die(“Connection failed”);

if($result = odbc_exec($conn, $query)) {

echo “Query returned : ” . odbc_num_rows($result) . “rows”;

odbc_result_all($result);

}

?>

python -m SimpleHTTPServer 80

This creates a simple Webserver on port 80 and its root path is the directory it ran from. For more details about it, visit python docs: http://docs.python.org/library/simplehttpserver.html

A simple how to use:

1. Save the winmail.dat to your home directory, probably a temp folder in your home directory.
2. Open the terminal and change the directory to the place where the winmail.dat is saved.
3. Run the command:
   ytnef -f . winmail.dat
   It will save the files in the current directory.

This morning I woke up and one of Fayrooz songs was playing in my head! I thought of Downloading all of them. So, I found a good website (http://www.6rb.com/music/Singers-13/525.html) with many Fayrooz songs ( I can’t say all because I don’t know them all). Anyway, that’s how I downloaded the Songs and converted them to MP3

You will require those packages:

wget, grep, mplayer, and lame

Procedure:

First, I wanted a list of the files to be extracted from the website, so I save the page as a text file:

wget -O output.txt “http://www.6rb.com/music/Singers-13/525.html”

Secondly, extract the links: (Assuming you know what is grep and cut)

grep .rm output.txt|grep http|cut -d\” -f4 > links.txt

Now, we require to download the songs:

wget -i links.txt

Grab a cup of coffee and wait till download is done!

Since I wanted the files to be MP3′s instead of real media to burn them on a CD for my car, so we have to convert them to MP3′s.

The idea is to convert them to waves using Mplayer and then encode them using lame.

To Convert one file to wave:

mplayer filename.rm -ao pcm:file=filename.wav -vc dummy -vo null

Then encode,

lame -m m filename.wav filename.mp3

I created a script to convert all the files in one directory so simplify the process for me.

Simply, dd is tool to convert or copy a file.. And what is lovely about *NIX based systems have disks and most hardware as hardware nodes accessible as files! Usually, on Linux, hard disks are accessible via /dev/hd[a] (For ATA Drives) or /dev/sd[a] (For SCSI or SATA Drives).

First Scenario is to image the hard drive to a USB disk, Assuming that we have booted a Linux Live CD, The USB Disk mounted to /media/disk and the hard disk is accessible via /dev/sda.

We run:

dd if=/dev/sda of=/media/disk/hard-disk-image-name.img

Note: if = input file, and of = output file

Now, lets say we want to restore the image to hard disk:

dd if=/media/disk/hard-disk-image-name.img of=/dev/sda

What if we want to save the image compressed and restore it from a compressed file, Assuming that you know gzip.

Disk to image compressed:

dd if=/dev/sda | gzip -9 | dd of=/media/disk/hard-disk-image-name.img.gz

Restore compressed Image to disk:

dd if=/media/disk/hard-disk-image-name.img.gz | gzip -d | dd of=/dev/sda

Ok, now all the above is about saving to an image on a USB disk, how about we want to write to an image or disk over the network, we have two options here, using SSH or Netcat!

I will be providing examples using Netcat, however, over SSH is similar, Its the same concept.

Disk to Disk or image over network (Its a matter of chaning the output file), assuming that we have booted a Live CD and we have a network configured on both linux machines on Network: 10.0.0.0/24, Master Machine IP: 10.0.0.1, and slave Machine is 10.0.0.2

Disk to disk over network, as I said above, it could be written to a USB disk image by changing the output file:

On Slave:

nc -l -p 9000 | dd of=/dev/sda

Note: Netcat options are as follows: -l is to listen to a port, -p to specify the port number to listen on.

On Master:

dd if=/dev/sda | nc 10.0.0.2 9000

Note: Netcat is going to connect to the slave machine IP and port as specified above.

Now, you can even using gzip over network if you are conservative about the bandwidth!

The Installation:

It’s really nice, very fast and responsive.. It gave me the option to copy the DVD to the hard drive, it really improves the install time!

Updates:
After a full install, the whole update for my all packages was only about 530MB to download! Unlike Fedora that required 1.2GB of downloads!!

Overall:
Mandriva is a very good Distro, everything comes on the DVD. Giving the option to have a full running system to do your job even without internet connection. Unlike Ubuntu!

for i in `ls`; do old=$i; new=`echo $i | tr [:upper:] [:lower:]`; mv $old $new; done;

And all files in the same directory are converted to lower case.

1. eth0 driver is doing 100 interrupts per second.
after reading “modinfo forcedeth”, I had to create a file in /etc/modprobe.d/forcedeth and have the following line in it:

options forcedeth poll_interval=65534

This reduced the number of interrupts.

2. nvidia driver was consuming much of power too.. After reading its manual and searching the internet. I had to modify my /etc/X11/xorg.conf to have the following:
In the driver section:

Option “RegistryDwords” “PowerMizerEnable=0×1; PerfLevelSrc=0×2222; PowerMizerDefault=0×3; PowerMizerDefaultAC=0×2″

What I have done here is I have disabled Nvidia powermizer and I have set the clock to the lowest speed when running on battery and on mid speed when running on AC.

In the Screen section:

Option “OnDemandVBlankInterrupts” “True”

3. Kernel Tuning for laptop…
I. Enable laptop mode:

echo 5 > /proc/sys/vm/laptop_mode

II. Virtual Memory:

echo 40 > /proc/sys/vm/dirty_ratio
echo 10 > /proc/sys/vm/dirty_background_ratio
echo 1500 > /proc/sys/vm/dirty_writeback_centisecs

4. Laptop mode tools:

http://samwel.tk/laptop_mode/

For Kernel tuning, I have created a script that got the default values for kernel parameters and the tuned values so that I run the script with parameters to switch between modes.

rdate uses NTP to get time from network and set it or print it on the workstation/server.

To use rdate:

$ rdate [options] [ntpserver]

[options]:
-s Set the system time to the returned time.
-p Print the time returned by the remote machine.

The next step was to find an NTP server. So I found a good list in NIST Internet Time service.

So, I run the command:

$ rdate -s time-a.nist.gov

And my clock is synchronised.