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Posts Tagged ‘Ubuntu’

Installing eAccelerator In Ubuntu Server

December 26, 2010 4 comments

eAccelerator is a free open-source PHP accelerator & optimizer. It increases the performance of PHP scripts by caching them in their compiled state, so that the overhead of compiling is almost completely eliminated. It also optimizes scripts to speed up their execution.

“eAccelerator typically reduces server load and increases the speed of your PHP code by 1-10 times.” – eAccelerator

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How to change the hostname in Ubuntu

February 26, 2009 36 comments

To change hostname in Ubuntu or any Debian variant Linux, modify the /etc/hostname and /etc/hosts.

sudo vi /etc/hostname

Change the old hostname to a new hostname.

sudo vi /etc/hosts

Also, change the oldhostname to a new hostname,

192.168.1.100               newhostname

After done, changing the /etc/hostname and /etc/hosts, you need to restart the hostname service.

sudo /etc/init.d/hostname.sh stop

sudo /etc/init.d/hostname.sh start

And then you log out from the shell and log in back. Once logged in, type

hostname

to check on the changes you have made for the hostname.

Categories: Linux / Unix, Tutorial, Ubuntu Tags:

Ubuntu auto shutdown due to high CPU temperature

February 23, 2009 40 comments

Ubuntu

I use a laptop with Ubuntu 8.10 installed at work. While running the some high process, the CPU temperature get really high and its automatically shutdown the system. This thing happen every 2 or 3 days and its really annoying. The syslog showed the following error message:

ACPI: Critical trip point
Critical temperature reached (100 C), shutting down.

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How to setup headless Sun xVM VirtualBox on Ubuntu server

September 4, 2008 20 comments

The steps are not too difficult but I did have to find a few places for information. Search on the forum turn up nothing on this subject so hopefully this HOWTO would be helpful to someone out there.

Note: This is not using the OSE version.

Background:
VirtualBox has a very good GUI running on the host to manage guest OS. However when running a server, we typically do not want to run X on it. Fortunately VirtualBox has commandline tools to manage guest systems. It also provides the VirtualBox Remote Desktop Protocol (VRDP) to allow connection to the guest remotely.

Clarification of terms used:
Host – refers to the machine we are trying to install VirtualBox.
Guest – the VirtualBox guest system that is setup on the host.
Remote – the PC that we are working on to connect to the host via SSH.

This setup was done on a fresh install of Ubuntu Server 8.04 with openssh-server installed.

All the following steps are done by SSH into the host from a remote (I’m using Windows for now).

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Fix date and time in Ubuntu

June 20, 2008 30 comments

Dual-booting with Ubuntu and Windows sometimes giving a problem with date and time in Ubuntu. This is a well-established problem when dual-booting, since Linux assumes the hardware clock represents UTC, whereas Windows assumes the hardware clock represents local time. Luckily Linux provides ways to change this to fix it.

If you go into your clock settings, I think you can select between setting the hardware as either UTC or local time. Try switching that, and then adjust the time and see if it “sticks.”

If not, you can do this via the commandline in Linux :-

  1. In Linux, set the date and time to what it currently is. For example if it’s 10:20am local time:
    user@server:~$ sudo date -s 10:20
  2. Then update the hardware clock accordingly, and force this to be considered “localtime”:
    user@server:~$ sudo /sbin/hwclock --systohc --localtime
  3. Check to make sure it looks right:
    user@server:~$ sudo /sbin/hwclock --localtime
  4. Sync between hardware clock and system clock:
    user@server:~$ sudo /sbin/hwclock --hctosys --localtime

Now Linux should consider the clock to be “localtime”, which should be identical to what Windows is doing. So after rebooting into Windows, the time should look right.

Hope that helps.

Fix for No Splash in Ubuntu 7.10

March 31, 2008 Leave a comment

After installing Ubuntu 7.10 there is no splash screen displayed at startup nor at shutdown. I just get a ‘Signal Out of Range’ message from my monitor.

A program called usplash controls this process, so I looked into it’s configuration, the values were totally off for my monitor, which uses a resolution of 1280 x 800.

By default the file looks like:
$ sudo cat /etc/usplash.conf
# Usplash configuration file
xres=1280
yres=1024

I edited the file:
$ sudo gedit /etc/usplash.conf

I changed the xres to: xres=1080 and the yres to: yres=800. Then I reconfigured the usplash program with the new settings.
$ sudo dpkg-reconfigure usplash

Problem fixed, now the splash image displays both at startup and shutdown.

Categories: Linux / Unix, Tutorial Tags: ,

Restore GRUB in Ubuntu

November 23, 2007 Leave a comment

Restore GRUB quite simple in Ubuntu, instead going through all the “gain root access” and play with shell commands, you can use the Ubuntu installation CD to restore it without going through all kinds of hassles.

Here are the steps:

  1. Boot your computer up with Ubuntu CD
  2. Go through all the process until you reach “[!!!] Disk Partition”
  3. Select Manual Partition
  4. Mount your appropriate linux partions
    /
    /boot
    swap
  5. DO NOT FORMAT THEM.
  6. Finish the manual partition
  7. Say “Yes” when it asks you to save the changes
  8. It will give you errors saying that “the system couldn’t install …..” after that
  9. Ignore them, keep select “continue” until you get back to the Ubuntu installation menu
  10. Jump to “Install Grub ….”
  11. Once it is finished, just restart your computer

Another way to restore GRUB, for advance users.

  1. Pop in the Live CD, boot from it until you reach the desktop.
  2. Open a terminal window or switch to a tty.
  3. Type “grub”
  4. Type “root (hd0,6)”, or whatever your hard disk + boot partition numbers are (my /boot is at /dev/sda7, which translates to hd0,6 for grub).
  5. Type “setup (hd0)”, or whatever your hard disk number is.
  6. Quit grub by typing “quit”.
  7. Reboot.

Good luck!!!

Categories: Linux / Unix, Tutorial Tags: , ,
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