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Forcing reboot

A Linux Server is not Windows XP and if reboot fail you usually still connect by SSH and do something. This commands will show you how to remotely hard reboot machine. Hard reboot mean that shutdown scripts will not run and machine reboot immediately without syncing hard disk drives, shutdown applications etc, it’s more like hitting the reset button.

echo 1 > /proc/sys/kernel/sysrq

echo b > /proc/sysrq-trigger

This commands enable sysrq and after this calls fast reboot. If you want to force shutdown machine try this.

Force shutdown

echo 1 > /proc/sys/kernel/sysrq

echo o > /proc/sysrq-trigger

This came handy, when I had a server that had some IO error and it can no longer read from disk, only few cached binaries into memory kept it running (kernel, SSHD, bash), I could still access the machine via SSH but can no longer do anything, forcing the reboot as mentioned above was my only resort, and it worked like charm…

This tutorial is based on Falko Timme’s tutorial for MySQL Cluster 5.0. It shows how to configure a MySQL 5.1 cluster with five nodes: 1 x management, 2 x storage nodes and 2 x balancer nodes. This cluster is load-balanced by an Ultra Monkey package which provides heartbeat (for checking if the other node is still alive) and ldirectord (to split up the requests to the nodes of the MySQL cluster).
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Virtuozzo includes a utility to update itself and the included templates. To run this, you will need to ssh into the hardware node and execute the command:

vzup2date

In order to update the templates, add a -t to the command thusly:

vzup2date -t

It should be noted that if Virtuozzo is installed on the server, the standard Redhat up2date command should never be run.

If you are running Virtuozzo on a Windows server, then you can run the Virtuozzo update utility accessed through the Start menu.

Want to be notified instantly when someone logs into your server as root?

No problem, check out this nice tutorial on email notification for root logins. Keeping track of who logs into your server and when is very important, especially when you’re dealing with the super user account. We recommend that you use an email address not hosted on the server your sending the alert from

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To make sure MySQL uses the query cache, there are a few variables you need to set in the configuration file . Usually its my.cnf or my.ini so check on your server with the shell command locate , in our case we are running on a CentOS 5.2  distro and to its my.cnf located in /etc so we opened it by using :   nano /etc/my.cnf

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Moving mySQL DBs from one server to another:

mysqldump -uUSER -pPASSWORD txp_database > txp_database.sql

puts the entire thing in one nicely portable text file.

on a new server it takes

mysql -uUSER -pPASSWORD txp_database < txp_database.sql

to import it.

Cron allows users to automate repetitive system administration tasks such as tape backups, database reorganization, and general file cleanups (such as emptying log files and queues).

The Crontab File’s Syntax
To tell cron what you want it to run, and how often you want it to run it, you need to create a crontab file. A crontab file is just a text file with the following syntax:

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Taking backup of mysql database using cron

Create a file called database_backup.sh and also an empty directory called mysql_backup. The database_backup.sh script should have the following info :

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The great people from R-FX Networks are bringing us a number of powerfull tools for the Linux Server enviroment

PRM (Process Resource Monitoring) monitors the process table on a given system and matches process id’s with set resource limits in the config file or per-process based rules. Process id’s that match or exceed the set limits are logged and killed; includes e-mail alerts, kernel logging routine and more…

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Whenever you can’t remember Root password, you can read this tutorial and do step by step to Reset it … You can log in with single-user mode and create a new root password.
Reboot your computer. When GRUB is presenting the menu list, follow those instructions:

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