I have an Oracle 11g installation running in virtual machine (under Xen). Oracle is used for APEX development and some host few local applications for our team. From time to time I need to do cold backups – to keep data around or to move them to another VM on different server, which is running identical version of oracle and can be used as cold backup eventually. The backup device is an USB disk with FAT32 filesystem (FAT32 was chosen a while ago for compatibility reason – to be able to attach it to almost any OS) and the disk is attached to other server. FAT32 means that there is a limit on file size, so the database backup need to be split to chunks (backup is 10-15 GB). Of course RMAN can do proper job, but since I’m no real DBA I want to have something quick ( data are not mission critical and also it is no problem to bring DB down) – so warning do not apply this procedure for important databases – no guarantee that it will work in all circumstances and you may loose your data . Continue reading Quick And Dirty Oracle Backup
GSetttings is the standard way how Gnome 3 applications store their configuration. GSettings is the front-end interface for application, actual values are stored by back-end – standard one is called dconf. We can then use the tool dconf-editor to easily browse all stored configurations for all applications. Thanks to GObject introspection we can also work easily with GSettings from python. Continue reading GSettings – Flexible Configuration System
Recently I needed to record some screen-cast from Linux desktop. In past I was using gtk-recordmydesktop, which basically worked well, but I thought maybe there is something better. And I have found this combination of two tools very useful – Kazam (screencaster) and OpenShot (video editing) . Kazam is easy to use with all basic functions that are needed (screen area definition, multi-display support, audio source selection) and it supports output into two common formats (MP4, WebM). When screen-cast is finished Kazam gives you opportunity to open it directly with a video editor – here OpenShot can be used to cut your screen-cast video, add titles etc. and finalize screen-cast video. Continue reading Nice Solution for Recording Screencasts on Linux
Debian/Ubuntu do not have bash autocompletion enabled for root account by default. When working under root account, this is quite missed feature, but luckily it can be enabled very easily:
apt-get install bash-completion # if not installed - like in minimal Debian install
add folowing to the file:
if [ -f /etc/bash_completion ]; then
I need to use superuser privileges quite often and not so particular about security, but still want to work mainly under my own user. The solution is to set sudo not to require password for my user:
add following line to the end:
As noted this is basically a security risk, so apply only if you are sure what you are doing.
Having heard so much about clouds and ‘Infrastructure as A Service’ recently I decided to try Openstack – complete open source solution for cloud computing. Openstack is actually a set of softwares, that together provide necessary services for a cloud infrastructure. Openstack (Essex release) can be installed in virtual machine, Virtual Box in my case, so I gave it a try and here are some of my observations: Continue reading Partly Cloudy – Openstack in VM
After upgrade to the new version of Linux (Mint 13, which is based on Ubuntu Precise) I’d found that my trackpoint is not working right (on Dell E6410), it was bit unresponsive and movement was not smooth. Touchpad was generally OK, but trackpoint really sucked. So I had to look into details of mouse setup in X and I was really surprised how many various parameters are there and how many aspects of mouse behaviour could be modified. So I’d like to share few tips how to set pointing device – apart of those obvious settings, which are available in desktop settings (Acceleration and Sensitivity).
Visual Python or vpython is python library for simple 3D animation, especially useful for animation of simple physical scenes – like pendulum, ball on a spring, movement in gravitational field etc. It is fairly simple to use and gives quite nice animations, which can demonstrate some laws of physics. I actually spot this package, when I saw an article about physics in popular mobile game “Angry Birds – Space”. In that article they had been arguing about physics laws in the game and also referred to vpython, where they made some experiments. I told myself I have to try it myself, so I’ve created small program using vpython. Continue reading Having 3D fun with Visual Python