DRBD split-brain solution in primary/primary setup

Recently one of our customers DRBD cluster has detected split-brain: This is  primary/primary cluster. And to fix this issue we had to perform manual procedures since we don’t use automatic recovery feature. According to the DRDB official documentation the solution is next. The problem is drbdadm doesn’t have  ‘–discard-my-data’  option and exits with error: The…
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RPM: last installed packages

1. To get list of last installed RPM packages you can simply use next command: 2. To get list of packages installed sorted by size use: Didn’t find the answer to your question? Ask it our administrators to reply we will publish on website.

Getting idle processes PID from Perl

There is a nice lib for Perl for working with processes in Linux. And it could be used to get PIDs of processes that have been working more than some amount of time. Now you can use simple wrapper to kill them gracefully. Didn’t find the answer to your question? Ask it our administrators to…
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How to backup and restore your LDAP database

LDAP is Lightweight Directory Access Protocol. It is a way to communicate with directory services. And for many years it has proved its reliability to organize and keep various type of information, for instance, user accounts. It’s useful if you want to provide one credentials for accessing to different resources – servers, web pages, etc….
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Using SNMP extend feature in Nagios

In Supportex we monitor a lot of web services and devices. One of the most convenient ways to monitor various parameters is SNMP extend feature. Let’s consider how it works. Assume you already have SNMP daemon installed. Firstly you need to add configuration line in you SNMP daemon config and restart daemon: extend raid-md0 /usr/local/bin/check_md_raid.pl…
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Three ways to make MySQL database dump

Everybody knows – backups are very important. Today a lot of web projects use MySQL to keep data. So you need to know how to set up reliable but simple backup of all your databases. And even if you are only developing you might probably need some tools to make quick dumps and to restore…
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How to determine RAID controller type and a model

Almost all modern servers are shipped with RAID controllers – redundant array of independent disks. Despite the fact that this technology was invented more than twenty years ago, nowadays the importance of it can scarcely be exaggerated.  In most cases your hosting provider cares about RAID initial setup. So if you don’t want to know…
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