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How to measure disk performance with fio and IOPing

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Introduction Whether it’s a server, or a PC for work, what usually limits performances is disk speed. Even if using SSDs, their speed is not yet comparable to that of RAM and CPU. There are different tools with or without a graphical interface, written for testing disks speed. There are also people who use  dd , for example: dd if=/dev/zero of=test_file bs=64k count=16k conv=fdatasync However, in our opinion dd is the worst software for benchmarking I/O performance. In fact: it is a single-threaded, sequential-write test. Of course, if running a web server, services do not do long-running sequential writes, and use more than one thread it writes a small amount of data, so the result can be influenced by caching or by RAID’s controller it executes for just a few seconds, and everyone knows that in this way it’s not possible to have consistent results there are no reading speed tests All these points just lead to one conclusion: better to use anything else. For disk benc
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Install MariaDB 10.1 on Fedora 25/24, CentOS/RHEL 7.3/6.8/5.11

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MariaDB is a binary drop in replacement for MySQL database server. This means that for most cases, you can just uninstall MySQL and install MariaDB and you are good to go. Why MariaDB? MariaDB is totally open source version of MySQL It works just like MySQL and is compatible with MySQL setups Fedora and Red Hat/CentOS is moving to use MariaDB from Fedora 19/RHEL 7/CentOS 7 versions This is guide,  howto install or upgrade MariaDB 10.1.20 [stable] (10.0.28 [stable] or 10.2.2 [beta] or 5.5.53 [stable]) on Fedora 25/24/23, CentOS 7.3/6.8/5.11 and Red Hat (RHEL) 7.3/6.8/5.11 . Installing MariaDB is almost same process than install MySQL. Note: If you are moving from MySQL, then make sure that you backup (dump and copy) your database and configs. And if upgrading from earlier versions, then remember run mysql_upgrade command. And if you uninstall MySQL, then remember restore /etc/my.cnf after installation, like: Bash mv -vi /etc/my.cnf.rpmsave /etc/my.cnf Install M
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How to install LDAP on CentOS 7

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Introduction LDAP stands for Lightweight Directory Access Protocol  and, as the name suggests, it’s a standard protocol for accessing and maintaining distributed directory information services over an IP network. In this tutorial, we’ll install a LDAP server on Centos 7 using 389 Directory Server. Getting started First of all,  configure FQDN in /etc/hosts . In that file, put the server’s fully qualified domain name. 127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4 ::1 localhost localhost.localdomain localhost6 localhost6.localdomain6 X.X.X.X yoursever.hostname.lan server Of course, substitue the last line in this example with your server’s informations. Configure firewall As you may know, we need to allow LDAP server’s default ports via firewall in order to access it from a remote system. So: firewall-cmd --permanent --add-port=389/tcp firewall-cmd --permanent --add-port=636/tcp firewall-cmd --permanent --add-port=9830/tcp Now, resta
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Install and configure Jenkins on Ubuntu 16.04

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Introduction Jenkins  is an automation server written in Java, as a fork of the  Hudson  project. It helps to automate part of the software development process, with aids like continuous integration, but also by further empowering teams to implement the technical part of a Continuous Delivery.  Jenkins  supports many SCM (Source Control Management) software systems including  Git ,  SVN , and  Mercurial  and provides hundreds of plugins to automate projects. This tutorial explains how to install and use Jenkins on Ubuntu 16.04 using Apache as server . Install Java Jenkins  requires Java, so, install  OpenJDK7  on the server. First, install  python-software-properties : # apt install python-software-properties Then you can add Java repository: # add-apt-repository ppa:openjdk-r/ppa Update Ubuntu repos and install OpenJDK: # apt update # apt install openjdk-7-jdk Run  $ java -version  to verify that you have OpenJDK7 correctly installed. Install Jenkins Jenkins team
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How to generate and check strong passwords in Linux

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Introduction Different operations require different security layers. Accessing your email account, your social media, your bank account, and a remote server that you administer through SSH all need different security layers, and contain data which hold different “weight”. But, in order to accessing all these operations, you will always require the same thing:  a password . We all know that a strong password is what you really need in order to be protected from attacks, and, of course, we all know that it’s better to use different passwords for different services. A very unwise decision (and common mistake) would be using your server password to access Facebook. This decision could cause you lots of trouble. So how can we easily manage the task of creating strong passwords? In this tutorial, we will talk about how to generate and check your passwords . Generate a strong password A strong password should be composed of a mix of alphabet characters, numbers, and symbols. A second
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