.::Polaris's personal blog::. - Techie

Quick Guide: Unable to boot Linux after installation.

adi.hazman@gmail.com (polaris) — Wed, 09 Aug 2006 14:27:34 +0800

If you had problem to boot linux (any flavor that uses grub as the boot loader), and all you get is a blank screen after all of those BIOS messages.. it might be something is wrong with your grub installation.

Below is a guide on how to resetup grup.

1. Boot to linux rescue

2. chroot /mnt/sysimages

3. cd /boot/grub

4. check that all grup.conf setting is correct

5. check that devices.map is correct (use grub-install --recheck device-name , to rebuild the file)

6. run command below:

shell# grub
grub> root (hd0,0)
grub> setup (hd0)
if you have more than 1 disk and it is mirrored, proceed with the following

grub> root (hd1,0)
grub> setup (hd1)
grub> quit (to exit from grub shell)

7. remove the cdrom from the machine and reboot.

8. now you should be able to boot the machine.

Quick Guide: Setting up initial MySQL root user password

adi.hazman@gmail.com (polaris) — Tue, 08 Aug 2006 16:14:51 +0800

After a successfull installation of MySQL you need to set an initial password for your mysql root user.

below are a quick way to do that (For Linux installation):

shell> mysql -u root mysql

mysql> SET PASSWORD FOR root@localhost=PASSWORD('new_password');

TIP: how to exclude files in find command

adi.hazman@gmail.com (polaris) — Tue, 18 Apr 2006 13:45:06 +0800

This is how you could use find command to exclude files/file pattern.

in Solaris

# find /var ! $ -name filename -o -name filename.* $ -print

where ;

! = not equal to ( in solaris cannot use "-not")
\( = begin complex expresssion

-o = or

\) = end complex expression

In linux ;

# find /var -not $ -name filename -o -name filename.* $ -print

where ;

-not = not equal to ( ! can also be used as in solaris)

\( = begin complex expresssion

-o = or

\) = end complex expression

source : http://www.athabascau.ca/html/depts/compserv/webunit/HOWTO/find.htm

Quick guide to ssh passwordless login with different users

adi.hazman@gmail.com (polaris) — Wed, 18 Jan 2006 16:27:32 +0800

Have you ever had problem with ssh passwordless login using different users?

Below are step by steps guide that solved that problem.

Senario :

User johndoe on machine pluto is accessing user foo on server mercury, without entering any password..

The Guide:

1. on pluto, johndoe need to generate his own private/public key pairs (i'am using dsa)

pluto# ssh-keygen -t dsa

- when asked for a password, leave it blank, just press "Enter" twice.

the key pairs will be saved in $HOME/.ssh/ (id_dsa and id_dsa_pub)

2. copy over id_dsa_pub to foo at mercury, then add the content of id_dsa_pub to foo's $HOME/.ssh/authorized_keys

mercury# cat id_dsa_pub >>authorized_keys

3. make sure foo's $HOME/.ssh directory permission is set to 700.

mercury# chmod 700 $HOME/.ssh

4. Now the important part: make sure to enable these settings on mercury's /etc/ssh/sshd_config

ForwardAgent yes
PubkeyAuthentication yes
StrictModes no

most people forgot to sets these settings that make them unable to ssh with different user, without a password.

5. restart sshd deamon.

mercury# /etc/inti.d/sshd restart

6. ok you're done, try ssh from pluto

pluto# ssh foo@mercury

By now you already should logon to foo on mercury without the need to key-in foo's password...

ok good luck....

.::Polaris::.

How to use Orca on linux servers.

adi.hazman@gmail.com (polaris) — Wed, 04 Jan 2006 13:10:37 +0800

How to use ORCA on linux server ( using procalator)

Below are step by step guide to use orca on linux servers, please bear in mind that this is for my personal reference only, please use it at your own risk. I written this guide since i haven't find it anywhere on google/internet.

What you need to have (read the procalator README for details) :

1. procalator (included in your source distribution of orca (mine is 0.27): contrib/procalator)

2. a running orca server (not covered here).

3. perl 5 installed on all target servers

installation:

Client site..

You can use procalator without compiling the source distribution, provided that you have a running orca server as no. 2 above.

1. unpack the source distribution;

# tar xvfz orca-0.27.tar.gz

2. go to orca-0.27/contrib/procalator

# cd orca-0.27/contrib/

3. copy all files in orca-0.27/contrib/procalator to your targeted machine.

# tar cvf ./procalator.tar ./procalator

# scp procalator.tar root@polaris:/tmp/temp

(can use other means to copy your files to other machine ie ftp,sftp etc..)

4. in you targed machine installed procalator (read the README for details)

** you might need to change the permission for procalator, install.sh and procallator.pl.in to 755.

** copy procallator.pl.in to procallator.pl

5. run install.sh

#./install.sh

6. that is you're done!! check that your procallator is running.

#ps -eafd |grep procallator

root 7613 1 0 13:07 pts/0 00:00:00 /bin/sh /etc/init.d/procallator start
root 7614 7613 0 13:07 pts/0 00:00:00 initlog -q -c /usr/local/bin/procallator.pl
root 7615 7614 0 13:07 pts/0 00:00:00 /usr/bin/perl -w /usr/local/bin/procallator.pl

7. verify that the data is written to /usr/local/var/orca/$hostname .

8. if you read the README, there is a script to upload those data to the ORCA server, you can use rsync, ftp etc. put it in your $prefix/var/orca/orcallator/$hosname in the server. use crontab to update the data frequently.

Server site...

There is nothing much to do, all you need is to run orca with procalator.cfg.

You might need to edit a few parameters, ie base_dir, html_dir and find_files to the correct path that suit your installation

# /path/to/orca /path/to/procallator.cfg

** you can use -v and -l if you need to log the output..

# /path/to/orca -v -l /var/log/orca.log procallator.cfg

i guess that is all you need to do to use orca on you linux servers. good luck trying..

.::Polaris::.

Jan-04-2006 : 13:54

Streamyx at last...

adi.hazman@gmail.com (polaris) — Wed, 23 Nov 2005 13:58:58 +0800

Finally i'am surfing the net via streamy at home, pergh.. what a long wait.. but then it worth it. Unlimited use, free modem and installation, and 512kpbs for only RM45 per month, i guess that is the best choice you can get around here..

i've done a bandwith test just now, got only 394.24kbps as expected, TM already told me that my house is quite far from their exchange, 6km, you need at least below 5km to get a good connection. so far 394.24kpbs is still acceptable to me.

below is the screenshot output from the test:

Webbased application is the way to go...

adi.hazman@gmail.com (polaris) — Wed, 05 Oct 2005 11:06:34 +0800

Now i know why microsoft should be worry about google... it's because it trying to make the web as the new platform for any applications .. all you need is a web browser, it doesn't matter in what platform/os you are running.. SUN is right with it vision of "The Network is the Computer " check out all these new/beta application.. ( this is the way of the future.. )

http://www4.meebo.com/
http://online.thinkfree.com/index.jsp
http://www.writely.com/

most of these application are using AJAX,

can you imagine a few years ahead, you are reading your webmail as if using your fav. mail client such as outlook, that you simply can drag/drop you messages to another folder.. , viewing mail properties, and a lot more similar features, just using your web browser...

here's a few screen shots..

Palm is using Microsoft Windows Mobile 5.0???

adi.hazman@gmail.com (polaris) — Wed, 28 Sep 2005 09:23:45 +0800

Just can believe it !!, that my fav. handheld is using Microsoft Windows Mobile 5.0, what happen to Palm OS??? i used to own Palm M505, with Palm OS 4.0, unfurtunely the batery dies a year ago.. , never had the time to fix it..

but it's really surprising that now Palm (treo) is using microsoft.. dammed...!!!, probably this is the results of Palm separating it hardware and software (Palm OS) unit.

http://www.bharian.com.my/m/BHarian/Wednesday/Komputer/20050928075848/Article/

http://news.zdnet.com/2100-1040_22-5884040.html?tag=nl.e589

Episode 10 : The new empire is striking ...

adi.hazman@gmail.com (polaris) — Thu, 22 Sep 2005 09:43:43 +0800

Google is becoming a new empire.. microsoft better watch out.. may the force be with you..

"But unlike Sun and Oracle, Google's timing could be impeccable. "Sun defined it. Ellison tried to build it. But Google owns it," he said."

http://news.zdnet.com/2100-9588_22-5875433.html?tag=nl.e589

p/s : google talk anyone.. ?

SUN Blade 100 and 300GB Maxtor disk..

adi.hazman@gmail.com (polaris) — Mon, 05 Sep 2005 16:57:52 +0800

we just bought a 300GB Maxtor disk at about RM570, the planned was to stuff it into a SUN Blade 100, our netbackup media server to use as stagging space before be written into a tape library..

Only to find out that the blade does not support more that 137GB harddisk due to hardware limitation, their IDE controlled does not support it.. dammed..!!!

now i have to find out.. how make the blade use the 300GB ??? wa.. how about external usb.. hmm, it might work.. , well got to try first..

hmm.. or better maybe i could swap it with my 30GB from my desktop.. hihihi syyy....

my wife new compaq presario..

adi.hazman@gmail.com (polaris) — Wed, 22 Jun 2005 15:38:17 +0800

Last sunday, my wife bought a new compaq presario notebook for about RM 3200, The notebook comes with Intel Centrino Mobile Tech. , 256MB RAM, 40GB HD, Combo drive, and completed with wifi and bluetooth.. and not forgotten the 6 in 1 card reader..

as of writing this, with the new compaq !, i'am quite satisfied with it, even though i've to get a new replacement due to wifi problem yesterday. it's actually, not that easy to get the replacement, had to argue a little bit with sales person before their bos agreed to replace with the new one.

i've almost done configuring it... still thinking what else to install.. hmm.. aaa.. i know,
Nero burning ROM... ok guys.. got to googled for Nero.. until then.. good day..

pissed off...!!!

adi.hazman@gmail.com (polaris) — Wed, 01 Jun 2005 12:13:07 +0800

Since yesterday my desktop realy makes me pissed off.. don't know why but i keep getting the famous Blue-screen-of-death, dammed it, what else to do, but REBOOT!!.. i guess i have rebooted my desktop for the 4th times since this morning.. aarrrghh..

if it happen again. while typing this i guesss the best solution probably.. throw this dammed desktop to the wall and see it explode.. !!! har.. harrr. harr..!!! (bengang nih..).

i guess the problem, probably with the memory, cause from the error messages it's says something about memory fault etc.. , hmm where can i find a good memory to swap..aaa.. hihihihi...

firefox ranked number 1 and editor's choice !!!

adi.hazman@gmail.com (polaris) — Wed, 25 May 2005 15:59:08 +0800

hurayyy....

my fav. browser won again.. !!!

qoute from http://www.spreadfirefox.com/

At c|net.com, in the Reviews area, they have an article titled: IE vs. the world: six Web browsers compared. This article compares the following six web browsers and tells which is the best (Editors' Choice) and which are the worst.

Ranked Number 1 and Editors' Choice - Firefox
CNET rating of 8

Coming in tied at 2nd - Netscape 8 and Safari RSS
CNET rating of 7.7

3-way tie for last place - Internet Explorer (with Windows XP SP2), Deepnet Explorer, and Opera 8
CNET rating of 7.0

read full review here at cnet

Load Average..

adi.hazman@gmail.com (polaris) — Wed, 18 May 2005 16:55:25 +0800

ok, today i'am going to write on something technical, what load average is all about.. ?
when we are talking about system performance, how fast or slow a system is ( ie, a server or workstation)?
In unix/linux we will use a performance monitoring tools such as top, vmstat, uptime etc..
when we run top or uptime as below :

#uptime
5:10pm up 50 day(s), 2 users, load average: 0.02, 0.02, 0.02

we can see there is an output of load average. So what the hell it's all about? what does it mean?
ok , i tell you what it's all about from my own understanding.. ,
load average = no. of average process /jobs in the run queue over a period of time (1, 5 and 15 min).

so then what?, how i can tell how slow or fast are my machine?,
quote from http://www.itworld.com/nl/unix_sys_adm/03202002/

"As a general rule of thumb, if load averages consistently exceed three times the number of CPUs on your system, your CPU is overworked. Averages less than 1 are acceptable. "

ok, i hope that explained what load average is all about, if your machine load average is not exceed 3 on a single CPU machine then it ok, but above that you're in trouble, eventhough you CPU is 90% idle... that mean maybe something other than CPU's is keeping the jobs from completing, ie I/O or memory etc..

My Desktop..

adi.hazman@gmail.com (polaris) — Thu, 12 May 2005 14:34:54 +0800

just updated my desktop with this great tool, Kapsule wow!! now it's completed.. !! all that i wanted is there.. , i'am really hates using Windows default desktop., it SUCK !!!. with that old start button, windows EXPLODER.. etc.. it just not me... , thats why i'am using all this alternatif shells.

check my new desktop below :

and here are details info of that desktop:

1. Shell : Litestep 0.24.7 RC 1
2. Litestep theme: simplicity by Omar Hussain
3. Kapsul and Widget