Tag Archives: linux

Install Oracle 12c on CentOS 7 – Part II

Note: This tutorial is just for installing/testing Oracle for personal purposes. If you are installing for some production environments, consult expert advice. This is a second part of two part blog on how to install Oracle 12c on CentOS 7. First part can be found here
Now create a user ‘oracle’ and groups ‘dba’ and ‘oracle’.
Then login into GUI using user ‘oracle’. Get the Oracle pre-requisites repo for their website. After setting up the repo, issue the command: Open the ‘terminal’ and go to the path where you have downloaded the Oracle 12 downloads
When you get the below GUI, un-tick the check box and proceed further. Follow the snapshots.
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Your choice for Desktop or Server class. My choice is server class as I wanted to understand the different options.
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As we are installing for development/testing purposes, ignoring few pre-requisites won’t matter.
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Database creation in progress.
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Your database details:
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On hitting the “Password Management” in the above screen you will get this screen. Change passwords of users you want to.
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We are done here installing Oracle! Now small tips. You can setup your centOS7 to start at run level 3. Refer THIS. Now with VirtualBox, you can use VBoxManage and VBoxHeadless to manage and run Virtual Machines from terminal and in background. And, install or enable SSH on your CentOS server. Refer THIS So if you have your own LAN set up. Go to network settings for this machine in VirtualBox and choose “Bridged Adapter”
Network Settings

Network Settings

To see all options of VBoxManage, hit enter after tying in VBoxManage on terminal. Now we can see that, it has listed two VM’s for me. We need CentOS7_X64. Now we will start it using VBoxHeadless. Now, get IP of your VM. And do this Set up your shell login script like below. Now logout and login again. And start your database and listeners: If port 1521 is open in firewall, then you can connect to this database from anywhere in your LAN. To shutdown database and CentOS server:

openSuSE 13.1 – Copy Paste memory use

Since I had installed openSUSE 13.1,copy pasting has been a real problem. Whenever doing a copy paste operation, the entire system became useless due to copy-paste process taking all the system memory.

This problem didn’t seem to be any application specific, as this problem was occurring in Dolphin, Konqueror as well as in Krusader . And when I checked “cp” command from the terminal, even that was causing the issue.

After a lot of search, I read somewhere that is the kernel that came with openSUSE 13.1 which has this issue with copy paste. The kernel version was 13.11.

I updated the kernel from openSUSE stable kernel repo to 13.13. And yes, the problem is gone! So it was a problem with kernel 13.11. My system is currently having kernel 13.14,and till now the system is running fine.

Did you face the same problem with kernel 13.11?

P.S: Usually I do not choose to make any updates to my system, as I like a very stable system, but this issue forced me to update what is the basis of any Linux system.

SQLDeveloper Fonts

I like Oracle’s sqldeveloper. It does a nice job and is free. So if someone has to learn Oralce or is working on Oracle DB as a hobbh, investing in Quest’s PlSQL Developer or Toad does not make sense, even if they provide a lot more functionality than Oracle’s SQL Developer.

What I do not like in SQL developer is its look and feel and fonts in it, which look so ugly. You can change the theme of developer to windows in windows which makes a bit better. But, in Linux there’s no choice. You have to work with Oracle theme.

Here is how I made it look a bit better for me.

Modify sqldeveloper/sqldeveloper/bin/sqldeveloper.conf to add below line: Instead of “Droid Sans” you can use and test whatever font you like.

Here is a before and after snapshot of my SQLDeveloper.

SQLDeveloper Before changes
Oracle SQLDeveloper before changes
SQLDeveloper After Changes
Oracle SQLDeveloper After changes

And, here is my sqldeveloper.conf after changes:

Linux – Know network usage by applications

A few days back, the network monitor was showing very high download speed in my openSuSE 11.4… even though I had no downloads or browsers running. This got me worried and a search began to find out the applications using network. Here is what I did. Install “iftop” from the repos. Just like “top”, “iftop” lists out the applications by their network usage. The command is: “-i” is for interface to use, I was on the wifi network so used “wlan0′. To check network usage for LAN or Cable network, the interface most probably will be “eth0”. [/caption] You can use “p” to toggle ports. Here the port used by first application is 25747. We will use this port to find out the application which is using network with the command “lsof”. Here below the “COMMAND” application name listed is “java”. Right now there is vuze running on my system which is downloading the latest openSuSE 12.1 DVD. This way you can check if there is some application using guzzling your network unnecessarily.