Archive for July, 2009

System Administrator Appreciation Day

0
July 31, 2009
by Kerem in

Today is the 10th annual System Administrator Appreciation Day. It is probably known and appreciated by only the sysadmins in the world, so only we appreciate our own work (it seems a little pathetic, isn’t it? :) )

I am a full time System Administrator in the company I work at. I keep the connectivity of the company up. I make sure most of the spam goes to the trash instead of users’ mailboxes. When the servers go down at 03:00 am, I get up from my bed and go fix the problem. I am not only a sysadmin but I also help our developers when they cannot do something traditionally by just coding, as I know how systems work and how problems can be solved using different ways.

I am not a real developer, yet I can code more efficiently at times because I know the inner workings of my systems.

I love my work even if people do not understand what I do. :)

So, happy sysadmin day to all who work hard to make this “internet thingamajik” go on working as intended…

http://www.sysadminday.com/

PS: You know that internet is wireless, right?

New PHP QR Code Generator Page

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July 11, 2009
by Kerem in ,

Checking my blog stats, I saw that most people come to my Real Time QR Code Generator PHP Function post. So, I decided to create a decent page for QR Code generation instead of linking to a URL which accepts only base64 encoded variables. The new page is PHP QR Code Generator page, and now you can, not only create an image that redirects you to a web address, but also can call a phone number, send an sms and send an e-mail. Also you can just encode plain text into a QR Code image.

UPDATE: vCard and bookmarks creation added.

Hope it proves to be useful for some people out there.

Supporting Oracle FCF in Tomcat

24
July 9, 2009
by Kerem in , , ,

We use Tomcat with Apache HTTPD in our company. And as a database backend, we use a two node Oracle Real Application Cluster (RAC).

We were having stale connection problems when a RAC node was behaving abnormally, because the JDBC pool which was created by Tomcat was not getting any notification about it. So I started searching for a way to take advantage of Oracle’s Fast Connection Failover (FCF) mechanism. FCF is superior to Transparent Application Failover (TAF) as it is event based and supports load balancing across the RAC nodes. It is also superior to having no failover mechanism whatsoever. :)

FCF leverages Oracle Notification Service (ONS) to get information about database events. With the help of ONS, a JDBC pool which has FCF enabled can see if a RAC node is up or down and can act accordingly. To be able to use the method I am about to show, you will have to have a minimum Oracle RAC version of 10.2.0, because Oracle versions prior to that do not support “Remote ONS”, which is an essential part of this configuration.

Continue reading...

Enabling tftpd on MacOS X (Snow) Leopard

1
July 8, 2009
by Kerem in ,

Enabling the tftp daemon in MacOS X Snow Leopard (or Leopard) is an easy task with little documentation. This is a quick reference. The manual page for tftpd in MacOS X Snow Leopard (or Leopard) recommends that tftpd is launched via launchd, so we will do it that way. First, we enter launchd% console using sudo:

sudo launchctl

After that, we enable tftpd in launchd% console:

load -F /System/Library/LaunchDaemons/tftp.plist

That’s it. Now you can put your tftp files into /private/tftpboot folder and start using tftpd.

When you are finished using the daemon, you can unload it by entering launchd% console and issuing the following command:

unload /System/Library/LaunchDaemons/tftp.plist

If you use tftpd a lot, you can enable it at boot time by entering the following in launchd% console:

load -w /System/Library/LaunchDaemons/tftp.plist

And to disable it from starting up at boot time:

unload -w /System/Library/LaunchDaemons/tftp.plist
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