How do configure to release and obtain VIP (virtual IP) when nginx is dead, down or system is rebooted for the kernel upgrades?

Edit /usr/local/etc/keepalived/keepalived.conf and add the following section to check whether nginx is alive or dead:
# vi /usr/local/etc/keepalived/keepalived.conf

Updated file on both lb0 and lb1:

vrrp_script chk_http_port {
script "/usr/bin/killall -0 nginx"
interval 2
weight 2
}
vrrp_instance VI_1 {
interface eth0
state MASTER
virtual_router_id 51
priority 101
authentication {
auth_type PASS
auth_pass Add-Your-Password-Here
}
track_script {
chk_http_port
}
virtual_ipaddress {
202.54.1.1/29 dev eth1
}
}

Save and close the file. Reload keealived:
# /etc/init.d/keepalived restart

If nginx died due to any issues keepalived will release master VIP and backup server will become active. When master nginx LB0 comes backs online, the backup LB1 will go down in backup state.

How do I configure nginx as failover reverse proxy load balancer in front of two Apache web servers under CentOS / RHEL 5.x?

nginx is a Web and Reverse proxy server. Nginx used in front of Apache Web servers. All connections coming from the Internet addressed to one of the Web servers are routed through the nginx proxy server, which may either deal with the request itself or pass the request wholly or partially to the main web servers.

Our Sample Setup
Internet--
|
============= |---- apache1 (192.168.1.15)
| ISP Router| |
============= |---- apache2 (192.168.1.16)
| |
| |---- db1 (192.168.1.17)
| |eth0 -> 192.168.1.11 ----------/
|-lb0==| /
| |eth1 -> 202.54.1.1 ----/
|
| |eth0 -> 192.168.1.10 ----------\
|-lb1==| / |---- apache1 (192.168.1.15)
|eth1 -> 202.54.1.1 ----/ |
|---- apache2 (192.168.1.16)
|
|---- db1 (192.168.1.17)
Where,

lb0 - Linux box directly connected to the Internet via eth1. This is master load balancer.
lb1 - Linux box directly connected to the Internet via eth1. This is backup load balancer. This will become active if master networking failed.
202.54.1.1 - This ip moves between lb0 and lb1 server. It is called virtual IP address and it is managed by keepalived.
eth0 is connected to LAN and all other backend software servers are connected via eth0.
nginx is installed on both lb0 and lb1. It will listen on 202.54.1.1. You need to configure nginx as reverse proxy server. It will connects to Apache1 and Apache2.
Install httpd server on Apache#1 and Apache#2 server. Configure them to listen on 192.168.1.15:80 and 192.168.1.16:80. Do not assign public IP to this box. Only activate eth0 via LAN.
Install MySQL / Oracle / PgSQL server on Db#1. Configure db server to listen on 192.168.1.17:$db_server_port. Do not assign public IP to this box. Only activate eth0 via LAN.
In short you need the following hardware:

2 load balancer reverse proxy servers (250GB SATA, 2GB RAM, Single Intel P-D930 or AMD 170s with RHEL 64 bit+keepalived+nginx)
2 Apache web servers (Software RAID-1, SCSI-73GBx2 15k disk, 6GB RAM, Dual Intel Xeon or AMD 64 bit CPU with RHEL 64 bit+Apache 2)
1 backup Apache web servers (Software RAID-1, SCSI-73GBx2 15k disk, 6GB RAM, Dual Intel Xeon or AMD 64 bit CPU with RHEL 64 bit+Apache 2)
1 database server (RAID-10, SCSI-73GBx4 15k disk, 16GB RAM, Dual Intel Xeon or AMD 64 bit CPU with RHEL 64 bit+MySQL 5)
1 Caching server (RAID-1, SCSI-73GBx2 15k disk, 8GB RAM, Dual Intel Xeon or AMD 64 bit CPU with RHEL 64 bit)
1 offsite backup server (RAID-6, 1TB SATAx4, 4GB RAM, Single Intel/AMD CPU with RHEL 64bit)
Slave database, storage, pop3 and SMTP server as per requirements.
Internet uplink 100Mbps+ or as per requirements.
Remove Unwanted Software From lb0 and lb1
Type the following commands:
# yum -y groupremove "X Window System"
# x=$(yum list installed | egrep -i 'php|httpd|mysql|bind|dhclient|tftp|inetd|xinetd|ypserv|telnet-server|rsh-server|vsftpd|tcsh' | awk '{ print $1}')
# yum -y remove $x
# yum -y install bind-utils sysstat openssl-devel.x86_64 pcre-devel.x86_64 openssl097a.x86_64
# /usr/sbin/authconfig --passalgo=sha512 --update
# passwd root

The above will remove X windows and other unwanted software from both lb0 and lb1.

Install Nginx On Both lb0 and lb1
Type the following commands to download nginx, enter:
# cd /opt
# wget http://sysoev.ru/nginx/nginx-0.8.33.tar.gz

Untar nginx, enter:
# tar -zxvf nginx-0.8.33.tar.gz
# cd nginx-0.8.33

Configure nginx for 64 bit RHEL / CentOS Linux:
# ./configure --without-http_autoindex_module --without-http_ssi_module --without-http_userid_module --without-http_auth_basic_module --without-http_geo_module --without-http_fastcgi_module --without-http_empty_gif_module --with-openssl=/lib64

Sample outputs:

....
nginx path prefix: "/usr/local/nginx"
nginx binary file: "/usr/local/nginx/sbin/nginx"
nginx configuration prefix: "/usr/local/nginx/conf"
nginx configuration file: "/usr/local/nginx/conf/nginx.conf"
nginx pid file: "/usr/local/nginx/logs/nginx.pid"
nginx error log file: "/usr/local/nginx/logs/error.log"
nginx http access log file: "/usr/local/nginx/logs/access.log"
nginx http client request body temporary files: "client_body_temp"
nginx http proxy temporary files: "proxy_temp"
nginx http fastcgi temporary files: "fastcgi_temp"
...
Install the same:
# make
# make install

Create nginx User Account
Type the following commands to create a user account:
# useradd -s /sbin/nologin -d /usr/local/nginx/html -M nginx
# passwd -l nginx

Configure nginx As Reverse Proxy Load Balancer On Both lb0 and lb1
Edit /usr/local/nginx/conf/nginx.conf, enter:
# vi /usr/local/nginx/conf/nginx.conf

Update it as follows:


pid logs/nginx.pid;
user nginx nginx;
worker_processes 10;

events {
worker_connections 1024;
}

http {
default_type application/octet-stream;

## Common options ##
include options.conf;

## Proxy settings ##
include proxy.conf;

## lb domains ##
include nixcraft.in.conf;
}
Edit /usr/local/nginx/conf/options.conf, enter:
# vi /usr/local/nginx/conf/options.conf

Update it as follows:


## Size Limits
client_body_buffer_size 128K;
client_header_buffer_size 1M;
client_max_body_size 1M;
large_client_header_buffers 8 8k;

## Timeouts
client_body_timeout 60;
client_header_timeout 60;
expires 24h;
keepalive_timeout 60 60;
send_timeout 60;

## General Options
ignore_invalid_headers on;
keepalive_requests 100;
limit_zone gulag $binary_remote_addr 5m;
recursive_error_pages on;
sendfile on;
server_name_in_redirect off;
server_tokens off;

## TCP options
tcp_nodelay on;
tcp_nopush on;

## Compression
gzip on;
gzip_buffers 16 8k;
gzip_comp_level 6;
gzip_http_version 1.0;
gzip_min_length 0;
gzip_types text/plain text/css image/x-icon application/x-perl application/x-httpd-cgi;
gzip_vary on;

## Log Format
log_format main '$remote_addr $host $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" "$http_user_agent" '
'"$gzip_ratio"';

Edit /usr/local/nginx/conf/proxy.conf, enter:


## Proxy caching options
proxy_buffering on;
proxy_cache_min_uses 3;
proxy_cache_path /usr/local/nginx/proxy_temp/ levels=1:2 keys_zone=cache:10m inactive=10m max_size=1000M;
proxy_cache_valid any 10m;
proxy_ignore_client_abort off;
proxy_intercept_errors on;
proxy_next_upstream error timeout invalid_header;
proxy_redirect off;
proxy_set_header X-Forwarded-For $remote_addr;
proxy_connect_timeout 60;
proxy_send_timeout 60;
proxy_read_timeout 60;

Edit /usr/local/nginx/conf/nixcraft.in.conf, enter:


## Connect to backend servers via LAN ##
## Reverse Proxy Load Balancer Logic ##
upstream nixcraft {
server 192.168.1.15 weight=10 max_fails=3 fail_timeout=30s;
server 192.168.1.16 weight=10 max_fails=3 fail_timeout=30s;
# only comes alive when above two fails
server 192.168.1.23 weight=1 backup;
}

server {
access_log logs/access.log main;
error_log logs/error.log;
index index.html;
root /usr/local/nginx/html;
server_name nixcraft.in www.nixcraft.in subdomain.nixcraft.in;

## Only requests to our Host are allowed
if ($host !~ ^(nixcraft.in|www.nixcraft.in|subdomain.nixcraft.in)$ ) {
return 444;
}

## redirect www to nowww
# if ($host = 'www.nixcraft.in' ) {
# rewrite ^/(.*)$ http://nixcraft.in/$1 permanent;
# }

## Only allow these request methods
if ($request_method !~ ^(GET|HEAD|POST)$ ) {
return 444;
}

## PROXY - Web
location / {
proxy_pass http://nixcraft;
proxy_cache cache;
proxy_cache_valid 200 24h;
proxy_cache_use_stale error timeout invalid_header updating http_500 http_502 http_503 http_504;
proxy_ignore_headers Expires Cache-Control;

proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}

# redirect server error pages to the static page /50x.html
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
Start nginx web server:
# /usr/local/nginx/sbin/nginx
# netstat -tulpn | grep :80
# echo ' /usr/local/nginx/sbin/nginx' >> /etc/rc.local

Fire a webbrowser and type domain name such as nixcraft.in:
http://nixcraft.in

References:
nginx wiki
Stay tuned, for rest of the firewall, security, SELinux, database, helper scripts and optimization configuration.

Keepalived provides a strong and robust health checking for LVS clusters. It implements a framework of health checking on multiple layers for server failover, and VRRPv2 stack to handle director failover. How do I install and configure Keepalived for reverse proxy server such as nginx or lighttpd?

If your are using a LVS director to loadbalance a server pool in a production environment, you may want to have a robust solution for healthcheck & failover. This will also work with reverse proxy server such as nginx.

Our Sample Setup
Internet--
|
=============
| ISP Router|
=============
|
|
| |eth0 -> 192.168.1.11 (connected to lan)
|-lb0==|
| |eth1 -> 202.54.1.1 (vip master)
|
| |eth0 -> 192.168.1.10 (connected to lan)
|-lb1==|
|eth1 -> 202.54.1.1 (vip backup)
Where,

lb0 - Linux box directly connected to the Internet via eth1. This is master load balancer.
lb1 - Linux box directly connected to the Internet via eth1. This is backup load balancer. This will become active if master networking failed.
202.54.1.1 - This ip moves between lb0 and lb1 server. It is called virtual IP address and it is managed by keepalived.
eth0 is connected to LAN and all other backend software such as Apache, MySQL and so on.
You need to install the following softwares on both lb0 and lb1:

keepalived for IP failover.
iptables to filter traffic
nginx or lighttpd revers proxy server.
DNS settings should be as follows:

nixcraft.in - Our sample domain name.
lb0.nixcraft.in - 202.54.1.11 (real ip assigned to eth1)
lb1.nixcraft.in - 202.54.1.12 (real ip assigned to eth1)
www.nixcraft.in - 202.54.1.1 (VIP for web server) do not assign this IP to any interface.
Install Keepalived
Visit keepalived.org to grab latest source code. You can use the wget command to download the same (you need to install keepalived on both lb0 and lb1):
# cd /opt
# wget http://www.keepalived.org/software/keepalived-1.1.19.tar.gz
# tar -zxvf keepalived-1.1.19.tar.gz
# cd keepalived-1.1.19

Install Kernel Headers

You need to install the following packages:

Kernel-headers - includes the C header files that specify the interface between the Linux kernel and userspace libraries and programs. The header files define structures and constants that are needed for building most standard programs and are also needed for rebuilding the glibc package.
kernel-devel - this package provides kernel headers and makefiles sufficient to build modules against the kernel package.
Make sure kernel-headers and kernel-devel packages are installed. If not type the following install the same:
# yum -y install kernel-headers kernel-devel

Compile keepalived

Type the following command:
# ./configure --with-kernel-dir=/lib/modules/$(uname -r)/build

Sample outputs:

checking for gcc... gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables...
checking for suffix of object files... o
...
.....
..
config.status: creating keepalived/check/Makefile
config.status: creating keepalived/libipvs-2.6/Makefile

Keepalived configuration
------------------------
Keepalived version : 1.1.19
Compiler : gcc
Compiler flags : -g -O2
Extra Lib : -lpopt -lssl -lcrypto
Use IPVS Framework : Yes
IPVS sync daemon support : Yes
Use VRRP Framework : Yes
Use Debug flags : No
Compile and install the same:
# make && make install

Create Required Softlinks

Type the following commands to create service and run it at RHEL / CentOS run level #3 :
# cd /etc/sysconfig
# ln -s /usr/local/etc/sysconfig/keepalived .
# cd /etc/rc3.d/
# ln -s /usr/local/etc/rc.d/init.d/keepalived S100keepalived
# cd /etc/init.d/
# ln -s /usr/local/etc/rc.d/init.d/keepalived .

Configuration

Your main configuration directory is located at /usr/local/etc/keepalived and configuration file name is keepalived.conf. First, make backup of existing configuration:
# cd /usr/local/etc/keepalived
# cp keepalived.conf keepalived.conf.bak

Edit keepalived.conf as follows on lb0:

vrrp_instance VI_1 {
interface eth0
state MASTER
virtual_router_id 51
priority 101
authentication {
auth_type PASS
auth_pass Add-Your-Password-Here
}
virtual_ipaddress {
202.54.1.1/29 dev eth1
}
}
Edit keepalived.conf as follows on lb1 (note priority set to 100 i.e. backup load balancer):

vrrp_instance VI_1 {
interface eth0
state MASTER
virtual_router_id 51
priority 100
authentication {
auth_type PASS
auth_pass Add-Your-Password-Here
}
virtual_ipaddress {
202.54.1.1/29 dev eth1
}
}
Save and close the file. Finally start keepalived on both lb0 and lb1 as follows:
# /etc/init.d/keepalived start

Verify: Keepalived Working Or Not

/var/log/messages will keep track of VIP:
# tail -f /var/log/messages

Sample outputs:

Feb 21 04:06:15 lb0 Keepalived_vrrp: Netlink reflector reports IP 202.54.1.1 added
Feb 21 04:06:20 lb0 Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth1 for 202.54.1.1
Verify that VIP assigned to eth1:
# ip addr show eth1

Sample outputs:

3: eth1: mtu 1500 qdisc pfifo_fast qlen 10000
link/ether 00:30:48:30:30:a3 brd ff:ff:ff:ff:ff:ff
inet 202.54.1.11/29 brd 202.54.1.254 scope global eth1
inet 202.54.1.1/29 scope global secondary eth1
ping failover test
Open UNIX / Linux / OS X desktop terminal and type the following command to ping to VIP:
# ping 202.54.1.1

Login to lb0 and halt the server or take down networking:
# halt

Within seconds VIP should move from lb0 to lb1 and you should not see any drops in ping. On lb1 you should get the following in /var/log/messages:

Feb 21 04:10:07 lb1 Keepalived_vrrp: VRRP_Instance(VI_1) forcing a new MASTER election
Feb 21 04:10:08 lb1 Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATE
Feb 21 04:10:09 lb1 Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE
Feb 21 04:10:09 lb1 Keepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.
Feb 21 04:10:09 lb1 Keepalived_healthcheckers: Netlink reflector reports IP 202.54.1.1 added
Feb 21 04:10:09 lb1 Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth1 for 202.54.1.1
Conclusion

Your server is now configured with IP failover. However, you need to install and configure the following software in order to configure webserver and security:

nginx or lighttpd
iptables
Stay tuned, for more information on above configuration.

So you have that Samba server up and running and you can connect to it from Windows and Mac with ease. But when you turn to another Linux box that doesn’t have Konqueror, Nautilus, or Dolphin you can’t figure out the riddle of connecting. Or maybe you want to have this share mounted at boot time? How do you manage it?From the command line of course. Yes there are plenty of GUI tools that will allow you to connect to a Samba share easily, but they don’t help you set up anything to connect automatically. For that you will need to employ a few command line tools. But once it is finished, your system will be seamless.

What you will need
First I am going to assume you have your Samba server set up and you are able to connect to it from other machines. Outside of that you will need only one piece of software installed on your Linux machine: smbclient. This will be in your distributions’ repositories so just open up your Add/Remove Software utility, search for smbclient, select it, and click Apply.
Once smbclient is installed you are ready to go.

A test
Let’s first test to make sure your Linux box can see the Samba share. You will need either sudo or root access to do this. Issue the command:
smbclient //IP_TO_SAMBA_SERVER/SHARE_NAME -U USERNAME
Where:

• IP_TO_SAMBA_SERVER is the IP address of your Samba server.
• SHARE_NAME is the share you want to connect to.
• USERNAME is the user name you connect to the share with.

• IP_TO_SAMBA_SERVER is the IP address of your Samba server.
• SHARE_NAME is the share you want to connect to.
• USERNAME is the user name you connect to the share with.

• IP_TO_SAMBA_SERVER is the IP address of your Samba server.
• SHARE_NAME is the share you want to connect to.
• USERNAME is the user name you connect to the share with.
• PASSWORD is the password for the Samba user

Over the last ten+ years I have seen Linux configuration tools come and go. In the early days there was the tried-and-true, all-powerful linuxconf that many thought would remain the one and only Linux configuration tool until the end of times. Well, we were wrong and linuxconf has pretty much died off. Why did linuxconf die? Because new tools, such as Webmin? came along.
Webmin arrived on the scene in 1997 and pretty much blew away the competition. Webmin is truly a one-stop shop for Linux configuration. It’s modular so you can add and remove modules as they are needed. Webmin can configure your system, servers, networking, hardware, clusters, you name it!
Even though Webmin is a web-based utility, it does not require a server to be installed or running. Webmin contains its own built-in server so you will not need Apache running. Webmin does have to be running in order to log in.
The easiest way to install Webmin is to open up your Add/Remove Software utility, do a search for webmin, and install it. Or you can go to the Webmin Site, download the the appropriate binary and let your package manager do the work for you. If you are wanting to install Webmin on a headless server you can do the following:

• Secure shell to your server
• Download the correct installation file using the wget command.
• Issue the command to install Webmin (such as rpm -ivh webmind-XXX.rpm (where XXX is the release number)

/etc/rc.d/init.d/webmin start

/etc/init.d/webmin start

http://IP_OR_DOMAIN:10000

Webmin Main Page

The Webmin Configuration Page

Controlling Webmin

Image via Wikipedia

echo $PATH

/usr/lib/qt-3.3/bin:/usr/kerberos/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/jlwallen/bin

PATH=$PATH:$HOME/bin:/opt

/usr/lib/qt-3.3/bin:/usr/kerberos/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/jlwallen/bin:/opt

$sudo fdisk -l

/dev/sda1 29 8369 66999082+ 83 Linux
/dev/sda2 * 8370 13995 45190845 7 HPFS/NTFS
/dev/sda3 13996 14593 4803435 5 Extended
/dev/sda5 13996 14593 4803403+ 82 Linux swap / Solaris

$sudo mount /dev/sda1 /mnt
$sudo mount --bind /dev /mnt/dev
$sudo mount --bind /proc /mnt/proc

$sudo cp /etc/resolv.conf /mnt/etc/resolv.conf

sudo chroot /mnt

#nano -w /etc/default/grub

#grub-install /dev/sda

#grub-install --recheck /dev/sda

#exit
$sudo umount /mnt/dev
$sudo umount /mnt/proc
$sudo umount /mnt
$sudo reboot

Dear Windows Professional Service Pack 2:

I didn't want to tell you this in person, because I thought it might be too complicated, and might take too long. After all, we've been together for a long time, almost five years and running now. I know, i know. I know you so well; your control panel, your installation procedures, even when you get mad and go all blue screen on me; what can I say, you kinda grew on me.

But to be honest, things have been going downhill for a long time now. What happened to that lean, fast OS that i first installed? You know, the one that ran Civ 4, Vice City, and even True Crimes without a problem? The one that burned DVD's, CD's, the one that shared music with my xbox without a problem? I don't know. It seems like you've let go of yourself, to be honest. You take over 20 minutes to boot up, you run Civ4 slowly, heck, you even freeze up on me now when i try to watch video. What happened windows? Did you get so confortable that you thought I'd just deal with it?

Well, i've been cheating. See, back in tenth grade, i messed around a bit with this chick, her name was Red Hat Linux. We met in school in my networking 5 class, and i got to know her pretty well. I was all up in her terminal, if you know what i mean . Well, I took her home, and we had a really rough one night stand. I decided she wsn't for me, and i went back to you, because i knew what i was missing. Well, Red Hat has a south african cousin, and her name's Ubuntu...she's kinda hot, too. SHe's got three cousins, Xubuntu, Edubuntu, and Kubuntu, too, and their all sexy.

Well, I guess this letter is to let you know that it's over. I'm not going back, either. You can tempt me with your games, and all the software, but it's alright. I can get to know ubuntu, i can learn to work her terminals. Her freeware. Her internet support. After all, what can i say...she's sexy, fast, and free. ANd you're expensive, bloated, and well, always sick with viruses. I'm done.

I know, i know. I freaked out and formatted you off my hard drive, and then i called you begging and pleading to take me back, and we had angry make up sex. But what was i thinking? I remembered all the bad times we had, and i called Ubuntu up and she understood me just fine. Before I knew it, we were hitting it off again. She installed really quickly, and didn't even need any drivers or anything. Worked beautifully. And did i remind you she's free?

So Windows Professional Service Pack 2, i'm leaving you for Ubuntu know. It's over, we had a good run, but all expensive, virus laden, bloated software relationships must come to an end, right? I guess that's just how it has to be.

Thanks for all the good times though! NOthing like a BSOD when i'm trying to watch a live debate on MSN or CNN, or crashign on me int he middle of civ4.


But i have to go now. It's time to get down and dirty with ubuntu, and if i ever really miss you again, i'll just drink it away with some WINE.

Sincerely,

Bruno


Thanks for Ubuntuforums .

                                          

mysqlcheck -p -u root virtual
Enter password:
virtual.accounts                              OK

mysqlcheck -p -u root virtual trivia
Enter password:
virtual.accounts                              OK

mysqlcheck -p -u root mysql db host proc
Enter password:
mysql.db                                           OK
mysql.host                                         OK
mysql.proc                                         OK

mysqlcheck -p -u root –databases payroll contact
Enter password:
payroll.last_name                                   OK
payroll.first_name                                  OK
payroll.SSN                                         OK
payroll.pay_rate                                    OK
contact.last_name                                   OK
contact.first_name                                  OK
contact.phone_number                                OK

mysqlcheck -p -u root –all-databases
Enter password:
contacts.names                                     OK
contacts.phone_numbers                             OK
contacts.trivia                                    OK
mysql.columns_priv                                 OK
mysql.db                                           OK
mysql.func                                         OK
mysql.help_category                                OK
mysql.help_keyword                                 OK
mysql.help_relation                                OK
mysql.help_topic                                   OK
mysql.host                                         OK
mysql.proc                                         OK
mysql.procs_priv                                   OK
mysql.tables_priv                                  OK
mysql.time_zone                                    OK
mysql.time_zone_leap_second                        OK
mysql.time_zone_name                               OK
mysql.time_zone_transition                         OK
mysql.time_zone_transition_type                    OK
mysql.user                                         OK

mysqlcheck -p -u root –repair virtual
Enter password:
virtual.accounts                              OK

mysqlcheck -p -u root –repair –extended virtual
Enter password:
virtual.accounts                              OK

mysqlcheck -p -u root –repair –quick virtual
Enter password:
virtual.accounts                              OK

How To Back Up MySQL Databases With mylvmbackup On Debian Lenny


mylvmbackup is a Perl script for quickly creating MySQL backups. It uses LVM's snapshot feature to do so.

To perform a backup, mylvmbackup obtains a read lock on all tables and flushes all server caches to disk, creates a snapshot of the volume containing the MySQL data directory, and unlocks the tables again.

This article shows how to use it on a Debian Lenny server.

I do not issue any guarantee that this will work for you!


1 Preliminary Note
I'm assuming that MySQL is already set up and running on your system. The system must use LVM, and the MySQL data directory (/var/lib/mysql) should have an LVM partition of its own (althouth that is optional).

If you have read Back Up (And Restore) LVM Partitions With LVM Snapshots you know that LVM snapshots require some unused LVM partition for the snapshot.

My test system has a second, currently unused hard drive /dev/sdb that will be used by mylvmbackup to create a temporary logical volume for the backup.

This is my current situation:

root@server1:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/server1-root
20G 808M 18G 5% /
tmpfs 252M 0 252M 0% /lib/init/rw
varrun 252M 56K 251M 1% /var/run
varlock 252M 0 252M 0% /var/lock
udev 252M 2.6M 249M 2% /dev
tmpfs 252M 0 252M 0% /dev/shm
/dev/sda1 471M 23M 425M 6% /boot
/dev/mapper/server1-mysql
8.9G 170M 8.3G 2% /var/lib/mysql
root@server1:~#

As you see, I have two LVM partitions, / and /var/lib/mysql (plus an LVM swap partition not shown here).

The volume group is named server1, and the volumes are named swap, root, and mysql:

root@server1:~# pvdisplay
--- Physical volume ---
PV Name /dev/sda5
VG Name server1
PV Size 29.52 GB / not usable 3.66 MB
Allocatable yes (but full)
PE Size (KByte) 4096
Total PE 7557
Free PE 0
Allocated PE 7557
PV UUID 0gCmpE-FGel-9ayg-E2yg-kkEu-B72X-kFvaye

root@server1:~#

root@server1:~# vgdisplay
--- Volume group ---
VG Name server1
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 1
Act PV 1
VG Size 29.52 GB
PE Size 4.00 MB
Total PE 7557
Alloc PE / Size 7557 / 29.52 GB
Free PE / Size 0 / 0
VG UUID PH5Hpc-jqeP-BFYs-wWlA-hu03-qwuQ-0cNIu3

root@server1:~#

root@server1:~# lvdisplay
--- Logical volume ---
LV Name /dev/server1/swap
VG Name server1
LV UUID RCeLCK-MO5p-xoMq-SwTT-n2NV-GaP6-GaemDp
LV Write Access read/write
LV Status available
# open 2
LV Size 1.00 GB
Current LE 256
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:0

--- Logical volume ---
LV Name /dev/server1/root
VG Name server1
LV UUID 5Wen7n-xYmh-MQz1-fKH5-0XXa-1y2t-V3PYbb
LV Write Access read/write
LV Status available
# open 1
LV Size 19.53 GB
Current LE 5000
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:1

--- Logical volume ---
LV Name /dev/server1/mysql
VG Name server1
LV UUID wk8yb6-fDl8-4tg3-tneT-1dDe-wWdy-AfGZ5I
LV Write Access read/write
LV Status available
# open 1
LV Size 8.99 GB
Current LE 2301
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:2

root@server1:~#

Here's an overview of my two hard drives:
root@server1:~# fdisk -l

Disk /dev/sda: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x0009353f

Device Boot Start End Blocks Id System
/dev/sda1 * 1 62 497983+ 83 Linux
/dev/sda2 63 3916 30957255 5 Extended
/dev/sda5 63 3916 30957223+ 8e Linux LVM

Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000

Disk /dev/sdb doesn't contain a valid partition table
root@server1:~#

2 Preparing /dev/sdb
Before we can create snapshots on /dev/sdb, we must partition it (Linux LVM) and add it to our volume group (server1).

I will now create the partition /dev/sdb1 and add it to the server1 volume group:

# fdisk /dev/sdb
server1:~# fdisk /dev/sdb


Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel Building a new DOS disklabel.


Changes will remain in memory only, until you decide to write them. After that, of course, the previous
content won't be recoverable.

The number of cylinders for this disk is set to 1305.

There is nothing wrong with that, but this is larger than 1024, and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

Command (m for help): <-- n
Command action
e extended
p primary partition (1-4)
<-- p
Partition number (1-4): <-- 1
First cylinder (1-1305, default 1): <-- [ENTER]
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-1305, default 1305): <-- [ENTER]
Using default value 1305

Command (m for help): <-- t
Selected partition 1
Hex code (type L to list codes): <-- 8e
Changed system type of partition 1 to 8e (Linux LVM)

Command (m for help): <-- w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
pvcreate /dev/sdb1
vgextend server1 /dev/sdb1

That's it - we don't need to create any volumes on it - this will be done by mylvmbackup automatically.


3 Installing And Using mylvmbackup
Debian Lenny provides a package for mylvmbackup, therefore we can simply install it as follows:

# aptitude install mylvmbackup

Take a look at

# man mylvmbackup

to learn how to use it (read the part about InnoDB tables carefully if you're using InnoDB).

The mylvmbackup configuration file is /etc/mylvmbackup.conf, so you can either specify your options on the command line or in that file (command line options will override the options in /etc/mylvmbackup.conf).

The default backup directory is /var/cache/mylvmbackup/backup (unless you specify another location).

A sample command for backing up MyISAM tables would be:

# mylvmbackup --user=root --password=yourrootsqlpassword --mycnf=/etc/mysql/my.cnf --vgname=server1 --lvname=mysql --backuptype=tar

And for InnoDB:
# mylvmbackup --user=root --password=yourrootsqlpassword --innodb_recover --skip_flush_tables --mycnf=/etc/mysql/my.cnf --vgname=server1 --lvname=mysql --backuptype=tar

Make sure you fill in the right password, volume group name (server1 here) and the volume name of the volume that contains the MySQL data (the volume is /dev/server1/mysql, therefore the name is mysql).

I everything goes well, you should see lots of output:

root@server1:~# mylvmbackup --user=root --password=yourrootsqlpassword --mycnf=/etc/mysql/my.cnf --vgname=server1 --lvname=mysql --backuptype=tar
20100127 19:16:58 Info: Connecting to database...
20100127 19:16:58 Info: Flushing tables with read lock...
20100127 19:16:58 Info: Taking position record...
20100127 19:16:58 Info: Taking snapshot...
File descriptor 3 left open
Logical volume "mysql_snapshot" created
20100127 19:16:58 Info: Unlocking tables...
20100127 19:16:58 Info: Disconnecting from database...
20100127 19:16:58 Info: Mounting snapshot...
20100127 19:16:59 Info: Copying my.cnf...
20100127 19:16:59 Info: Taking actual backup...
20100127 19:16:59 Info: Creating tar archive /var/cache/mylvmbackup/backup/backup-20100127_191658_mysql.tar.gz
backup/
backup/mydb/
backup/mydb/sys_modules.MYI
backup/mydb/dns_a.frm
backup/mydb/isp_dienste.MYD
backup/mydb/isp_server_ip.frm
backup/mydb/dns_spf.frm
backup/mydb/dns_a.MYI
backup/mydb/isp_fakt_dep.frm
backup/mydb/multidoc_dep.frm
backup/mydb/isp_isp_web_template.MYI
backup/mydb/sys_nodes.MYD
backup/mydb/listtype.MYD
backup/mydb/help_documents.MYD
backup/mydb/help_tickets.MYI
backup/mydb/doctype.frm
backup/mydb/login.MYI
backup/mydb/isp_com.frm
backup/mydb/help_documents.MYI
backup/mydb/isp_dep.MYD
backup/mydb/help_documents.frm
backup/mydb/isp_server.MYD
backup/mydb/isp_fakt_nodes.MYD
backup/mydb/sys_config.MYD
backup/mydb/dns_nodes.MYI
backup/mydb/sys_config.MYI
backup/mydb/isp_monitor.frm
backup/mydb/isp_server_ip.MYI
backup/mydb/isp_isp_datenbank.frm
backup/mydb/dns_secondary.frm
backup/mydb/isp_nodes.MYI
backup/mydb/dns_isp_dns.MYI
backup/mydb/help_nodes.frm
backup/mydb/isp_fakt_nodes.frm
backup/mydb/isp_server.MYI
backup/mydb/isp_isp_domain.frm
backup/mydb/dns_dep.frm
backup/mydb/session.frm
backup/mydb/isp_isp_cron.MYD
backup/mydb/isp_fakt_record.MYI
backup/mydb/isp_monitor.MYI
backup/mydb/isp_fakt_rechnung.MYI
backup/mydb/listtype.MYI
backup/mydb/isp_fakt_rechnung.MYD
backup/mydb/isp_traffic.frm
backup/mydb/isp_fakt_dep.MYI
backup/mydb/user_groups.frm
backup/mydb/isp_fakt_record.frm
backup/mydb/isp_fakt_artikel.MYD
backup/mydb/isp_htaccess.MYD
backup/mydb/sys_nodes.frm
backup/mydb/groups.frm
backup/mydb/login.MYD
backup/mydb/isp_firewall.MYD
backup/mydb/isp_server.frm
backup/mydb/help_tickets.frm
backup/mydb/multidoc_dep.MYD
backup/mydb/dns_nodes.frm
backup/mydb/dns_a.MYD
backup/mydb/sys_config.frm
backup/mydb/dns_isp_dns.frm
backup/mydb/dns_mx.MYI
backup/mydb/isp_isp_web.MYD
backup/mydb/isp_serverstatus.MYI
backup/mydb/isp_serverstatus.MYD
backup/mydb/sys_dep.MYD
backup/mydb/isp_isp_cron.MYI
backup/mydb/session.MYD
backup/mydb/isp_isp_admin.MYD
backup/mydb/dns_ptr.frm
backup/mydb/dns_mx.frm
backup/mydb/isp_isp_domain.MYD
backup/mydb/sys_dep.MYI
backup/mydb/dns_spf.MYD
backup/mydb/user_groups.MYD
backup/mydb/sys_news.frm
backup/mydb/isp_isp_actions.MYI
backup/mydb/doctype.MYD
backup/mydb/multidoc_nodes.frm
backup/mydb/isp_fakt_artikel.frm
backup/mydb/sys_news.MYD
backup/mydb/isp_traffic.MYD
backup/mydb/user_groups.MYI
backup/mydb/sys_news.MYI
backup/mydb/listtype.frm
backup/mydb/del_status.frm
backup/mydb/isp_fakt_nodes.MYI
backup/mydb/isp_isp_kunde.MYD
backup/mydb/isp_dienste.frm
backup/mydb/dns_mx.MYD
backup/mydb/doctype.MYI
backup/mydb/help_tickets.MYD
backup/mydb/dns_secondary.MYI
backup/mydb/dns_ptr.MYD
backup/mydb/isp_isp_reseller.frm
backup/mydb/isp_dienste.MYI
backup/mydb/isp_isp_datenbank.MYD
backup/mydb/isp_isp_actions.MYD
backup/mydb/isp_isp_web.frm
backup/mydb/db.opt
backup/mydb/isp_server_ip.MYD
backup/mydb/multidoc_nodes.MYI
backup/mydb/dns_nodes.MYD
backup/mydb/isp_fakt_rechnung.frm
backup/mydb/isp_isp_reseller.MYI
backup/mydb/isp_nodes.MYD
backup/mydb/isp_htaccess.MYI
backup/mydb/isp_isp_web_template.frm
backup/mydb/isp_isp_domain.MYI
backup/mydb/dns_secondary.MYD
backup/mydb/dns_dep.MYD
backup/mydb/isp_firewall.MYI
backup/mydb/help_nodes.MYI
backup/mydb/isp_isp_admin.frm
backup/mydb/isp_isp_cron.frm
backup/mydb/isp_isp_datenbank.MYI
backup/mydb/isp_traffic_ip.frm
backup/mydb/isp_fakt_dep.MYD
backup/mydb/isp_dep.MYI
backup/mydb/dns_dep.MYI
backup/mydb/isp_isp_reseller.MYD
backup/mydb/dns_isp_dns.MYD
backup/mydb/isp_fakt_artikel.MYI
backup/mydb/multidoc_dep.MYI
backup/mydb/multidoc_nodes.MYD
backup/mydb/del_status.MYD
backup/mydb/groups.MYD
backup/mydb/isp_isp_web_template.MYD
backup/mydb/isp_htaccess.frm
backup/mydb/isp_dep.frm
backup/mydb/isp_isp_web.MYI
backup/mydb/isp_isp_user.frm
backup/mydb/session.MYI
backup/mydb/isp_isp_admin.MYI
backup/mydb/isp_isp_kunde.MYI
backup/mydb/isp_isp_user.MYI
backup/mydb/isp_fakt_record.MYD
backup/mydb/isp_nodes.frm
backup/mydb/groups.MYI
backup/mydb/del_status.MYI
backup/mydb/dns_spf.MYI
backup/mydb/isp_com.MYD
backup/mydb/isp_isp_user.MYD
backup/mydb/dns_cname.frm
backup/mydb/isp_com.MYI
backup/mydb/dns_cname.MYD
backup/mydb/sys_modules.MYD
backup/mydb/isp_traffic_ip.MYI
backup/mydb/help_nodes.MYD
backup/mydb/sys_user.frm
backup/mydb/isp_traffic_ip.MYD
backup/mydb/sys_user.MYD
backup/mydb/sys_modules.frm
backup/mydb/isp_serverstatus.frm
backup/mydb/sys_dep.frm
backup/mydb/isp_firewall.frm
backup/mydb/isp_monitor.MYD
backup/mydb/isp_isp_kunde.frm
backup/mydb/dns_cname.MYI
backup/mydb/isp_isp_actions.frm
backup/mydb/sys_user.MYI
backup/mydb/sys_nodes.MYI
backup/mydb/dns_ptr.MYI
backup/mydb/isp_traffic.MYI
backup/mydb/login.frm
backup/ib_logfile0
backup/mysql_upgrade_info
backup/debian-5.0.flag
backup/mysql/
backup/mysql/host.MYD
backup/mysql/procs_priv.MYD
backup/mysql/time_zone_transition.MYD
backup/mysql/proc.MYI
backup/mysql/time_zone_name.frm
backup/mysql/time_zone_name.MYD
backup/mysql/help_relation.MYI
backup/mysql/user.MYD
backup/mysql/help_category.MYI
backup/mysql/time_zone.frm
backup/mysql/func.MYD
backup/mysql/help_category.MYD
backup/mysql/time_zone_transition.frm
backup/mysql/time_zone_name.MYI
backup/mysql/help_category.frm
backup/mysql/time_zone_leap_second.frm
backup/mysql/time_zone_transition.MYI
backup/mysql/help_relation.MYD
backup/mysql/host.frm
backup/mysql/db.frm
backup/mysql/db.MYI
backup/mysql/columns_priv.frm
backup/mysql/time_zone.MYI
backup/mysql/time_zone_leap_second.MYD
backup/mysql/func.frm
backup/mysql/columns_priv.MYI
backup/mysql/help_topic.MYD
backup/mysql/host.MYI
backup/mysql/proc.frm
backup/mysql/user.MYI
backup/mysql/help_topic.MYI
backup/mysql/help_relation.frm
backup/mysql/tables_priv.frm
backup/mysql/help_keyword.frm
backup/mysql/user.frm
backup/mysql/time_zone_transition_type.MYI
backup/mysql/procs_priv.frm
backup/mysql/help_topic.frm
backup/mysql/procs_priv.MYI
backup/mysql/time_zone_transition_type.MYD
backup/mysql/func.MYI
backup/mysql/proc.MYD
backup/mysql/tables_priv.MYD
backup/mysql/help_keyword.MYI
backup/mysql/help_keyword.MYD
backup/mysql/time_zone_leap_second.MYI
backup/mysql/tables_priv.MYI
backup/mysql/db.MYD
backup/mysql/time_zone_transition_type.frm
backup/mysql/time_zone.MYD
backup/mysql/columns_priv.MYD
backup/lost+found/
backup/ibdata1
backup/ib_logfile1
backup-pos/backup-20100127_191658_mysql.pos
backup-pos/backup-20100127_191658_my.cnf
20100127 19:17:00 Info: DONE
20100127 19:17:00 Info: Cleaning up...
20100127 19:17:00 Info: LVM Usage stats:
20100127 19:17:00 Info: LV VG Attr LSize Origin Snap% Move Log Copy% Convert
20100127 19:17:00 Info: mysql_snapshot server1 swi-a- 5.00G mysql 0.00
Logical volume "mysql_snapshot" successfully removed
root@server1:~#

Afterwards you can find the backup in the /var/cache/mylvmbackup/backup directory (unless you have specified another location):

# ls -l /var/cache/mylvmbackup/backup
root@server1:~# ls -l /var/cache/mylvmbackup/backup
total 248
-rw-r--r-- 1 root root 246847 2010-01-27 19:17 backup-20100127_191658_mysql.tar.gz
root@server1:~#

The tar.gz file contains two directories, backup (with the databases and tables from /var/lib/mysql which you can simply copy back after a database crash - the database should be stopped when you do this) and backup-pos which contains your my.cnf file (a backup of /etc/mysql/my.cnf):

# cd /var/cache/mylvmbackup/backup
tar xvfz backup-20100127_191658_mysql.tar.gz
ls -l
root@server1:/var/cache/mylvmbackup/backup# ls -l
total 256
drwxr-xr-x 5 mysql mysql 4096 2010-01-27 19:10 backup
-rw-r--r-- 1 root root 246847 2010-01-27 19:17 backup-20100127_191658_mysql.tar.gz
drwxr-xr-x 2 root root 4096 2010-01-27 19:24 backup-pos
root@server1:/var/cache/mylvmbackup/backup#

4 Links
mylvmbackup: http://lenz.homelinux.org/mylvmbackup
MySQL: http://www.mysql.com
Debian: http://www.debian.org

How to make Your Ubuntu Linux Enegy Efficient using PowerTop







Since version 2.6.21, the Linux kernel has introduced a feature called tickless. the kernel no longer has a fixed 1000Hz timer tick.

This will give a dramatic power savings because the CPU stays in low power mode for longer periods of time during system idle.

A Nice handy tool, PowerTop has been created for reducing the Power Usage of Linux.

This application will help to find the software components that are preventing optimal usage of your hardware and give proper suggestions for both hardware and software configurations to reduce power consumption of your system.

So Now Your Ubuntu is energy Efficient.It is very useful for Laptop Users.


How To Install PowerTop in Ubuntu

Open a terminal and type the following

$ sudo apt-get install powertop

Or You can use Synaptic Package manager and select package powertop.

15 Remote Desktop Solutions for Linux.

There are a wide range of remote desktop applications that are available that can be used to connect to Windows environment but there aren’t too many that can be used to remote desktop from Linux to Linux or Windows to Linux.

With this I mean, getting entire desktop of remote Linux environment on your local workstation.

Most people who are used to a Unix-style environment know that a machine can be reached over the network at the shell level using utilities like telnet or ssh.

And some people realize that X Windows output can be redirected back to the client workstation. But many people don’t realize that it is easy to use an entire desktop over the network. There are a several of open source applications that can be used to achieve this.

1) VNC (Virtual Network Computing)
is a remote display system which allows the user to view the desktop of a remote machine anywhere on the internet. It can also be directed through SSH for security.

Basically you install VNC server on the server and install client on your local PC. Setup is extremely easy and server is very stable.

On client side, you can set the resolution and connect to IP of VNC server. It can be a bit slow compared to Windows remote desktop and also has the tendency to take more time refreshing over low-bandwidth links.

All in all VNC is an amazing piece of free software that gets the job done.

There is RealVNC , TightVNC and UltraVNC. Each has it’s advantages and disadvantages. Most popular one is RealVNC but if you’re upto it, experiment with all three and choose the one that works for you best.

By default, communication between client and server is in clear text on port 5900. However, you can easily route all traffic via SSH tunnel.

Here is a quick way of setting it up if you have access to command line shell:

# ssh -ND 5900 @remote.server.com

When you get prompted, enter your password. Pop open VNC client and connect to ‘localhost’. This’ll route your connection to VNC server on remote machine.

You can download VNC from:

• http://www.realvnc.com/download.html
• http://www.tightvnc.com/download.html
• http://www.uvnc.com/

2) Then there is FreeNX.
FreeNX is a system that allows you to access your desktop from another machine over the internet. You can use this to login graphically to your desktop from a remote location.

One example of its use would be to have a FreeNX server set up on your home computer, and graphically logging in to the home computer from your work computer, using a FreeNX client.

It provides near local speed application responsiveness over high latency, low bandwidth links.

FreeNX can be configured to run via SSH without any tunneling. It binds to your existing SSH install. Instead of guiding you through the installation of FreeNX in this article, you can visit the following URLs that’ll guide you through the installation on Ubuntu:

• https://help.ubuntu.com/community/FreeNX
• http://ubuntuforums.org/showthread.php?t=97277&highlight=freenx
• http://freenx.berlios.de/ (FreeNX homepage)

3) The third free application is 2X Terminal Server for Linux.
2X TerminalServer for Linux is an Open Source project, licensed under the GPL and is free of charge.

As far as performance goes, NoMachine’s technology is on par with Windows’ own Remote Desktop Protocol (RDP) suite, better than VNC.

Both X2 and FreeNX is based on NoMachine technology.

Here are some quick links if you’re interested in using this software:

• Download at http://www.2x.com/terminalserver/download.htm
• Forum is at http://www.2x.com/forums

4) Then there is is XDMCP.
The X Display Manager Control Protocol uses UDP port 177.

Compared to the list above, it’s not as easy to setup for remote desktop but it’s the original way of doing this on Linux.

You can get setup instructions and other tips in the following URL:

• http://www.tldp.org/HOWTO/XDMCP-HOWTO/intro.html

5) CygwinX.
A complete Linux emulation on Windows. You’ll find every tool and app that you have on Linux on Cygwin.

• Get it from http://www.cygwin.com

6) XRDP.
RDP server that runs on Linux, thus allowing you to use Windows Remote Desktop Client or rdesktop to connect.

• Get it from http://sourceforge.net/projects/xrdp/

7) x2vnc
great little utility that allows you to tie a linux and windows (or anything that can run the vncserver) together with a single keyboard/mouse, avoiding the need for a switcher box.

Mousing cross screens transparently switches between machines, and cut and paste works.

• Get it from http://fredrik.hubbe.net/x2vnc.html

8 ) Xming
It’s a great and lightweight implementation of X11 for Windows that allows you to connect to a Linux box.

• You can read about it at http://freedesktop.org/wiki/Xming

9) KDE Desktop Sharing (formerly krfb)
Part of KDE since version 3.1. It is located in the kdenetwork package. If your distribution splits the KDE applications into separate packets, you may find the client as ‘krdc’ and the server as ‘krfb’.

Also uses VNC technology.

10) X-Win32
Top rated PC X server solutions for Windows PCs connecting to remote Unix and Linux host systems.

Works well over SSH.

• Get it from http://www.starnet.com/products/xwin32/

11) Single Click UltraVNC
In case you would like to remote control without any software installed on the target computer you need UltraVNC SC.

The user on the to be controlled computer needs to simply click on a web page and remote controlling begins.

• Get it from here http://ultravnc.sourceforge.net/addons/singleclick.html

12) CrossLoop
CrossLoop is a FREE secure screen sharing utility designed for people of all technical skill levels.

CrossLoop extends the boundaries of VNC’s traditional screen sharing by enabling non-technical users to get connected from anywhere on the Internet in seconds without changing any firewall or router settings.

• Get it from http://www.crossloop.com/

13) Thinstation
Although not a remote desktop app but worth mentioning here. Thin client linux distro for terminals using std. x86 hw.

It can boot from network, pxe, syslinux,loadlin, CD, floppy or flash-disk and connect to servers using VNC, RDP, XDM, SSH and etc.

• Get it from http://sourceforge.net/projects/thinstation

14) rdesktop
an open source client for Windows NT Terminal Server and Windows 2000/2003 Terminal Services, capable of natively speaking Remote Desktop Protocol (RDP) in order to present the user’s NT desktop.

rdesktop currently runs on most UNIX based platforms with the X Window System, and other ports should be fairly straightforward.

• Download from: http://www.rdesktop.org/

While you’re at it, get grdesktop from (http://www.nongnu.org/grdesktop/). It is a GNOME frontend, for rdesktop.

It can save several connections (including their options), and browse the network for available terminal servers.

15) ssh -X
You can check out this great article written by a slashdot user sometime ago.

• Read it here http://slashdot.org/~Trolling4Dollars/journal/69740

Windows to Mac / Mac to Windows

1) RDP Client for Mac
allows you to connect to a Windows-based computer and work with programs and files on that computer from your Macintosh computer.

• Download it here

2) OSXVnc
Vine Server is a full featured VNC server for Mac OS X providing remote access to the GUI, keyboard and mouse using Vine Viewer or any other VNC client.

• Download it from http://www.redstonesoftware.com/products/vine/server/vineosx/index.html

3) Chicken of the VNC
A VNC client allows one to display and interact with a remote computer screen. In other words, you can use Chicken of the VNC to interact with a remote computer as though it’s right next to you.

• Download it from http://sourceforge.net/projects/cotvnc/

Unfortunately I was not able to find too many available to connect to Mac from Windows other than VNC.

I think Windows need to support RDP into Mac. Many people would benefit from this.

If I am missing anything from the list, please let me know.

Under many situations you may need to get a single file/many files from Linux ISO image.

You can mount ISO images via the loop device. You need to use mount command. First login as a root user:

Extract File(s) Under Linux OS

Let us assume that your ISO image name is disk1.iso.

Step # 1: First you need to create a directory /mnt/iso

# mkdir /mnt/iso
# mount -o loop disk1.iso /mnt/iso

Step # 3: Extract file

Now you can easily copy file called file.txt from iso disk image to /tmp directory :

# cd /mnt/iso
# cp file.txt /tmp

Step # 4: Copy foo.rpm from ISO disk image:

# cd /mnt/iso/RedHat/RPMS
# cp foo.rpm /tmp 

Extract File(s) Under Windows XP or Vista Os

Windows do not have in built capability as provided by Linux to extract file. Luckly many third party software exist my favorite is Winimage http://www.winimage.com/. Download trial version (I’m sure you will love to registered this tiny utility later):

1) Install Winimage software

2) Just double click on Linux ISO file

3) Select the desired file and hit CTRL + X (or from Image menu select extract)

For more information read man pages:

man cp
man mv
man rpm
man mount
man mkdir

With every new release of Ubuntu, there s a new XSplash theme that comes in. Today we show you how to change it and also show you some cool themes you might want to add to your machine.
XSplash
XSplash is a software project in the Ubuntu community that uses the X Window System to replace the scrolling-text screens that appear while booting a Linux-based computer with a graphical splash screen.
Previous versions of Ubuntu, (before Karmic Koala) used USplash which now is history. The default XSplash screen in Karmic Koala looks something like the one below& which is actually not too bad.

However, you don t have to live with the default XSplash if you don t like it. You can always change your XSplash screen to make it look better, and customize it to your Ubuntu overall theme. The following is the XSplash screen that I am currently using.

Change Themes
In order to change the XSplash screen in Ubuntu Karmic Koala follow these steps:
1. Open nautilus as root by typing  gksu nautilus at the run prompt (Alt + F2).
2. Download the XSplash archive that you want to use and move the content of the archive to

/usr/share/images/xsplash folder.

Note: Make sure that you take the back up of your current XSplash, by copying the default files to some safe location before copying the new XSplash theme files.
Once you have installed the new XSplash theme you can check how it looks by typing the following command at the terminal.

sudo xsplash