Author Archives: George Valentin Voina

Back-up of /home of a running system using lv snapshot

By | October 21, 2017

Following is a simple and easy way to do a consistent back-up of the /home directory (usually mounted in a separate partition) on a running system. We do not have the luxury of being able to stop the operations of a server and unmount the home partition to make sure no changes are done during… Read More »

Find in Linux if your installed RAM is ECC

By | October 21, 2017

Sometimes really simple questions are hard to answer. One day I got the question from a coworker: “How do I know if some installed RAM is ECC or not”. The easiest way is to use dmidecode command that dumps in Linux all the system characteristics. But because I had no idea how to see if… Read More »

#Docker : Fix services cannot see each other by name if they run on different swarm nodes issue

By | October 18, 2017

Lately after one of the updates of docker binaries I started to have a strange issue in a Docker Swarm setup configured here. Services were no longer able to see each other if they were running on different nodes. If two services were running on the same swarm node there was no issue. This is… Read More »

Having fun with #Conrad #RaspberryPi Advent Calendar – Days 1-5

By | October 20, 2017

In a perfect German tradition Conrad electronics shop released an Advent Calendar for Raspberry Pi. You can buy it online or from a Conrad shop if you get to go to Germany in a town with a Conrad shop. Got mine from the Conrad in Leipzig but online is available at Conrad Online There are… Read More »

#Oracle 12c invisible columns

By | February 20, 2021

“Invisible columns”: This is a new feature introduced in Oracle 12c that got me all excited.In short you can now have hidden columns in a table that are not visible to the standard SELECT, INSERT clauses if you do not want to. Some usage for this: Legacy application queries I hate how you have to… Read More »

#CrowdSourcing and #DataMining the new resource mining, or how big corporations are robbing you blind.

By | September 30, 2017

The newest commodity this days is crowd sourced data. All the digital corporations push this envelope harder and harder. Google wants to make me a “local guide”: post images of places on google maps and review businesses for free of course (they give you a badge, you know like boy scouts badges). This is lately… Read More »

Blog Links: Project management: A surefire way to kill your software product

By | September 27, 2017

One of the best articles about project management and software development Project management: A surefire way to kill your software product. As a software developer I have to agree with almost everything stated there and I can confirm most of it as true. You cannot treat creative people as resources and think that inspiration and… Read More »

#DRBD Growing online a replicated resource in a complex enterprise environment

By | October 20, 2017

At some point an increase in size of the replicated resource is needed. This can be caused by an increase in data retention times or an increase of transaction numbers affecting that resource. If the backing block devices can be grown while in operation (online), it is also possible to increase the size of a… Read More »

Set up automatic #Oracle database back-up using #RMAN

By | September 19, 2017

There is a very easy method of setting up on Linux an automatic back-up for Oracle by using database procedures, RMAN and scripts. STEP 1: Define a back-up script Create in /home/oracle/backup.sh a script file with the content: #!/bin/bash export ORACLE_HOME=/home/oracle/app/oracle/product/11.2.0/dbhome_1 export PATH=$PATH:$ORACLE_HOME/bin export ORACLE_SID=prod rman target / CMDFILE=/home/oracle/bin/backup.rman LOG /data/oradata/backuplogs/rman-`date -I`.log exit 0 Where… Read More »