Happy Ubuntu Linux

virtualbox memory management

2011-05-06T08:45:00.002-05:00

Memory ballooning

Starting with version 3.2, the Guest Additions of VirtualBox can change the amount of host memory that a VM uses while the machine is running. Because of how this is implemented, this feature is called "memory ballooning".

Note
VirtualBox supports memory ballooning only on 64-bit hosts, and it is not supported on Mac OS X hosts.

To change on the fly:

#VBoxManage controlvm "VM name" guestmemoryballoon

where "VM name" is the name or UUID of the virtual machine in question and is the amount of memory to allocate from the guest in megabytes.

To set a default balloon that will automatically be requested from the VM every time after it has started up:

#VBoxManage modifyvm "VM name" --guestmemoryballoon

Page Fusion

Whereas memory ballooning simply reduces the amount of RAM that is available to a VM, Page Fusion works differently: it avoids memory duplication between several similar running VMs.

In a server environment running several similar VMs (e.g. with identical operating systems) on the same host, lots of memory pages are identical. VirtualBox's Page Fusion technology, introduced with VirtualBox 3.2, is a novel technique to efficiently identify these identical memory pages and share them between multiple VMs.

Note
VirtualBox supports Page Fusion only on 64-bit hosts, and it is not supported on Mac OS X hosts. Page Fusion currently works only with Windows guests (2000 and later).

To enable Page Fusion for a VM, use the following command:

#VBoxManage modifyvm "VM name" --pagefusion on

Above content directly quote from virtualvox manual

VBoxManage Matricx

virtualbox 4.0.6 change vdi uuid

2011-05-05T16:19:00.004-05:00

Here is command to use to change uuid of vdi in ubuntu:

#VBoxManage internalcommands sethduuid [filehame.vdi] [uuid]

change filename.vdi and uuid to reflect correct vid name and uuid.

Combined Video files with ffmpeg

2011-02-01T08:09:00.002-06:00

# cat [video1].mpg [video2].mpg | ffmpeg -f mpeg -i - -vcodec copy -acodec copy [combined_video_file].mpg

Lighttpd FasCGI PHP, MySQL chroot jail installation under Debian Linux

2010-12-08T08:42:00.000-06:00

Found this HOWTO on secure lighttpd web server

Embedding flash player setup wizard

2010-01-01T13:50:00.001-06:00

Embedding flash player setup wizard

HOWTO: Easily enable MP3, MPEG4, AAC, and other restricted encoding in FFmpeg

2010-01-01T12:43:00.000-06:00

HOWTO: Easily enable MP3, MPEG4, AAC, and other restricted encoding in FFmpeg

Batch Convert mov files to flv files

2010-01-01T12:03:00.004-06:00

adopted from here Using FFMpeg to Convert mpg or mov to flv

I am using the code mentioned in the article to batch convert the mov files I took with my HD Camcorder to flv for streaming it online.

Here is the modified code to suit my needs:

if ($handle = opendir('.')) {
while (false !== ($file = readdir($handle))) {
if ($file != "." && $file != ".." && strpos($file, "MOV") !== false) {
$new_filename = str_replace(" ", "_", strtolower(str_replace("MOV", "flv", $file)));
$file = str_replace(" ", "\ ", $file);
exec("ffmpeg -i $file -s 640x360 -deinterlace -ar 44100 -r 25 -qmin 3 -qmax 8 $new_filename");
}
}
closedir($handle);
}
?>

I change the display ratio to half of the 720P.

How to make google chrome browser play youtube.com video with sound in Linux Ubuntu 9.1

2009-12-19T11:24:00.004-06:00

"No Sound!!!" When playing youtube.com video with google chrome in Ubuntu 9.1.

Here is how I solved it:

# sudo ln -s /usr/lib/mozilla/plugins /opt/google/chrome/plugins

Close/restart chrome browser.

Voila!! there's sound when playing youtube.com video

PPStream Totem Plug-in

2009-12-16T14:16:00.005-06:00

Plug-in for Totem to play video from PPStream.com

PPS Totem Plugin

Top things to do after installing Ubuntu Linux 9.10

Enable pidgin twitter support in Ubuntu 9.1

2009-12-10T08:28:00.002-06:00

To enable twitter plugin in pidgin IM one only need to install pidgin-mbplugin package

sudo apt-get install pidgin-mbplugin

ways to speed up Ubuntu

2009-04-03T08:12:00.003-05:00

Readahead Profile

Running boot-time scripts in parallel

Tweak & Optimize

SSH Port Forwarding

2009-02-25T07:16:00.000-06:00

SSH port forwarding

Logitech Quickcam Express + LInksys NSLU2

2009-02-04T17:09:00.003-06:00

This project is to configure a live webcam server.
Hardware:
1. Linksys NSLU2 with Debian Lenny installed.
2. Logitech Quickcam Express.

Software:
1. Quickcam Express driver.
2. webcam server.

Install:

1.Install Debian on NSLU2. I followed instruction from http://www.nslu2-linux.org

2. Install lighttpd webserver.

3. Install Quickcam driver.
a. sudo apt-get install module-assistant qc-usb-source qc-usb-utils

b. sudo m-a prepare.(follow module-assistant menu selection to Prepare, Compile, and Install quickcam driver.

4. reboot after install.

5. install and configure webcamserver follow instruction here

FCKeditor ASP html encoding problem solved

2008-03-06T21:30:00.003-06:00

I am working on a website project for a client which I need to incorporate 4 FCKeditor instances on the same page all generated html codes post into access database. All just doing well as after a little bit of hacking the html code posted into the database as expected and display on web page just perfect.

But then another problem arisen, the html code that stored in database didn't retrieved back into FCKeditor correctly when client tried to do content update. Consequently, the data posted back into database gets mass up. After did quite a bit of search on the net, I found out a hint from FCKeditor.net forum where a post described the same problem I am having. On that post a person replied that in order for the html code the be translated correctly those html code need to be save as string variable after retrieve from database before post into FCKeditor. So the following is what I did to get the job done.

////////////////////////////////////////////////////////////////////////////////////////////////
Dim sContent '//!!!!!!! VERY IMPORTANT TO DIM THE VAR OTHERWISE FCKEDITOR HTML ENCODE WON'T WORK !!!!!!!//
sContent = rstbl.Fields.Item("overview").Value
'//!!!!!! after var been declared data stored in var will be treated as STRING !!!!//
Dim oFCKeditor
Set oFCKeditor = New FCKeditor
oFCKeditor.BasePath = "/FCKeditor/"
oFCKeditor.Value = sContent
oFCKeditor.Width = 540
oFCKeditor.Height = 300
oFCKeditor.ToolbarSet = "Default"
oFCKeditor.Create "txtprdoverview"
///////////////////////////////////////////////////////////////////////////////////////////////

** I know this post is not Ubuntu Linux related but this is just a place where I keep a record.

DVD-RAM read/write in Ubuntu

2008-02-18T12:59:00.002-06:00

Following the Howto instructions found in this link http://ubuntuforums.org/showthread.php?t=129093

use mkudffs to format DVD-RAM.

Initially I am having problem format DVD-RAM disk after reading through the HOWTO it turns out was a user right issue.

I did a

"sudo chmod 777 /dev/pktcdvd/0"

then I can run

"mkudffs --media-type=dvdram /dev/pktcdvd/0"

without any error messages.

The rest is just follow Howto to mount the DVD-RAM disk.

Receive Ubuntu local delieved mail

2008-01-26T18:35:00.000-06:00

I am working on a script which is monitoring my software raid-1 raid array and sent event mail to local mail system.

By default, Ubuntu Gutsy dose not have local mail delivery system(message transfer agent "MTA") installed. The best way is to install mutt then all the dependents( exim4.....) for MTA will be installed as well.

After mutt installed, I configured Evolution to receive local mail.
In Evolution use user name as username@localhost and chose 'standard Unix mbox spool directory' as server type.

For testing, use mutt to send a testing mail then use Evolution to fetch the mail.

Fix Ubuntu Gutsy failed hibernate

2007-11-03T20:56:00.001-05:00

#sudo vim /etc/default/acpi-support

then

change the line POST_VIDEO=true to read POST_VIDEO=.

change "true" to "."

Evolution Backup

2007-10-28T15:00:00.000-05:00

Found a link on how to backup Evolution

Ubuntu Linux new version upgrade

2007-10-21T22:04:00.000-05:00

There's couple of ways to upgrade to new version of Ubuntu Linux. Of all those I found that use "apt-get upgrade via mounted iso image(alternate CD) is the most efficient way.

Here is how to do it.

1. Grab Ubuntu Linux alternate CD by using your favorite torrent client.

2. mount iso image to /media/cdrom (so that apt-cdrom can find it without any trouble)

# sudo mount -t iso9660 ubuntu-x.xx-alternatie-xxxx.iso /media/cdrom -o loop

3. add mounted iso image as port of apt sources.list

# sudo apt-cdrom -m add (-m tells apt-cdrom not to mount iso image, since it already mounted)

4. time to upgrade

# sudo apt-get dist-upgrade

5. Now it's time to grab a cup of whatever you like and sit back to let upgrade did the job.

6. After dist-upgrade done, use update manager for update system to most current state.

Send and Receive Hotmail through Evolution

2007-01-09T15:00:00.000-06:00

Followed the solution from this link send-&-receive email from hotmail in Evolution
, I am having my evolution fetching and sending email through my hotmail email account. The reason I used method in this link is it uses xinetd instead of inetd.

In the link it only mentioned about adding POP3 support to hotmail, I added the following code to make SMTP support for hotmail as well.

create /etc/xinetd.d/hotsmtpd

use following code as containts:

service hotsmtpd
{
#only_from = 192.168.1.0/8
disable = no
type = unlisted
socket_type = stream
protocol = tcp
wait = no
user = nobody
groups = yes
server = /usr/bin/hotsmtpd
#server_args = -p http://proxy:8080
port = 2500
}
** I use 2500 for smtp port**

This link gives detailed how to add hotmail account in Evolution.

Now, what I am looking for is the solution to be able to keep the file on mail server but deleted it when I deleted it from my local evolution mail client.

It all begins with this

2007-01-07T12:32:00.000-06:00

Ubuntu Linux