I am a new Ubuntu Linux laptop user. I setup my computer name to ‘tom’ during installation but now I would like to change the computer name to ‘jerry’. Can you tell me how do I I remove tom and set it to jerry on Ubuntu Linux? How do I change the Ubuntu computer name from ‘ubuntu’ to ‘AvlinStar’? Can you tell me more about Ubuntu Linux change hostname command?

You can use the hostname command to see or set the system’s host name. The host name or computer name is usually at system startup in /etc/hostname file. Open the terminal application and type the following commands to set or change hostname or computer name on Ubuntu.

Display the current Ubuntu hostname

Simply type the following command:
$ hostname
Sample outputs:

Ubuntu change hostname command

The procedure to change the computer name on Ubuntu Linux:

1. Type the following command to edit /etc/hostname using nano or vi text editor:
   sudo nano /etc/hostname
   Delete the old name and setup new name.
2. Next Edit the /etc/hosts file:
   sudo nano /etc/hosts
   Replace any occurrence of the existing computer name with your new one.
3. Reboot the system to changes take effect:
   sudo reboot

Sample outputs:

How to change the Ubuntu server hostname without a system restart?

Type the following commands:
$ sudo hostname new-server-name-here
Next edit the /etc/hostname file and update hostname:
$ sudo nano /etc/hostname
Finally, edit the /etc/hosts file and update the lines that reads your old-host-name:
$ sudo nano /etc/hosts
From:
127.0.1.1 old-host-name
To:
127.0.1.1 new-server-name-here
Save and close the file.

Ubuntu Linux Change Hostname Using hostnamectl

Systemd based Linux distro such as Ubuntu Linux 16.04 LTS and above can simply use the hostnamectl command to change hostname. To see current setting just type the following command:
$ hostnamectl
Sample outputs:

   Static hostname: nixcraft
         Icon name: computer-laptop
           Chassis: laptop
        Machine ID: 291893e6499e4d99891c3cf4b70a138b
           Boot ID: 9fda2365b77841649e40a141fde46537
  Operating System: Ubuntu 17.10
            Kernel: Linux 4.13.0-21-generic
      Architecture: x86-64

To change hostname from nixcraft to viveks-laptop, enter:
$ hostnamectl set-hostname viveks-laptop
$ hostnamectl

Source: Nico’s Blog

MySQL Master-Slave replication is natively supported by MySQL. However its configuration is not so simple. For each slave added as a replica, a few configuration steps must be done on both the master and itself.

So if you want to install a master instance on a machine or VM, and then install 5 other instances as slaves on other hosts, you will be doing quite a lot of back-and-forth configuration. I couldn’t find any way of configuring the replication automatically on the web, so I decided to create my own bash script to do it.

MySQL Master-Slave Replication

What is it and why use it ?

This form of replication is pretty simple: only a single instance, known as the master, creates or updates data. Each additional instance, called slave, simply keeps a copy of the master’s data, by replicating it each time the master has new data. Lire la suite…

Source: ryadel.com

We already had the opportunity to talk about Replication between MySQL Database in a previous article, where we described it as a great way to increase the security and reliability of data storage without spending a fortune. In this article we will see what to do when the Replication stops working: how to notice, what can I do to restore it and, most importantly, how to ensure that the data is re-synchronized.

Identify causes

The first thing to do is make sure that the Replication is actually broken. Although in most cases we can clearly see it by just looking at the replicated data, we need to check it in an objective way. In order to do this go to the Slave, issue the command SHOW SLAVE STATUS – or SHOW SLAVE STATUS\G if you prefer to read the results in human-readable format – and go read the column contents: Slave_SQL_Running and Slave_IO_Running: if there’s at least a NO, that means that the Replication is actually broken, otherwise the problem is attributable to other causes. Lire la suite…

Source: Optimiser les performances de MySQL (Quentin Busuttil)

Les bases de données SQL et plus particulièrement MySQL restent une des pierres angulaires de l’immense majorité des sites internet. MySQL fonctionne très bien out of the box, cependant, dès que la base se trouve assez sollicitée, on s’aperçoit que les réglages par défaut méritent une petite optimisation. Jetons un œil à tout ça !

Récemment, un des serveurs de Peerus commençait à avoir de sacrés pics de load lors des heures de forte charge, avec MySQL pour principal responsable. Une grosse centaine de connexions simultanées et quelques dizaines de requêtes par seconde sur des bases de plusieurs dizaines de giga. C’est un peu plus que le WordPress moyen, mais rien d’ingérable pour un MySQL bien réglé.

Dès lors, avant d’imaginer prendre un serveur plus puissant, sharder les tables ou je ne sais quoi encore, il faut tirer le maximum de notre cher SGBDR. Lire la suite…