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installing Oracle Instant Client on Linux

The Oracle Instant Client is a package that brings everything you need to connect to a Oracle Database. You can download it from Oracle with this Link.

With current Intel XEON Servers you should take the x86-64 package. But for 32-bit application you need the x86 package. You can install both in parallel, so it doesn't hurt if you take both. There are also several sub packages. You will only need the "Basic" or "Basic Lite" package if you want to run applications. If you want to build a application (like Perl DBD::Oracle or the PHP Oracle connector) You will also need the "SDK" package. If you want to run sqlplus, you will also need that package. You may also want to pick the right version for your database, but I experienced no problems with the newest client.

If you downloaded all you need the installation is as follows (tested on CentOS 5.2).

# install the RPMs
rpm -ivh oracle-instantclient11.1-basic-
rpm -ivh oracle-instantclient11.1-basic-
rpm -ivh oracle-instantclient11.1-sdk-
rpm -ivh oracle-instantclient11.1-sdk-

# set the libraries on the searchpath for the entire system
echo "/usr/lib/oracle/11.1/client/lib/" >> /etc/
echo "/usr/lib/oracle/11.1/client64/lib/" >> /etc/

# see if the libraries are included
ldconfig -p | grep oracle

Now you are ready either to run or build your application.

Have fun!

VMWare ESXi 3.5 and time sync

As you might already know VMWare and time sync are two things that don't play well together. Most times the time is off by some seconds or minutes or even better the time is not synchronized at all. I discovered today that ESXi 3.5 does not enable time sync by default. Even if you installed the VMWare tools!

To enable it, you need to log in into the Guest OS and execute the graphical program to adjust this setting. The program is "vmware-toolbox" and you simply need to activate the option "Time synchronization between the virtual machine and the ESX Server". Quite simple, but to do this you need either a X Server installed in the Guest OS or a forwarded X connection to a Workstation with a X Server. I personally don't like this, because it is complicated and you can't automate it. So I searched for a method to do this in a CLI interface.

After a bit of searching I found the following solution.

# Linux
vmware-guestd --cmd "vmx.set_option synctime 0 1" # Enable
vmware-guestd --cmd "vmx.set_option synctime 1 0" # Disable

# Windows
vmwareservice --cmd "vmx.set_option synctime 0 1" # Enable
vmwareservice --cmd "vmx.set_option synctime 1 0" # Disable

If time sync is already enabled, you will get a error message saying that the previous state is already set.

How to create a empty File in Linux

Well, it is realy simple to create a file in Linux, but some developers tend to use "special" commands to acheive it.

Here are the normal ones, I bet you know them:

touch $FILE
echo -n "" > $FILE
# (for temporary files)
mktemp ${FILE}.XXX

But these days I was confronted by a astonishing new solution to that problem:

cp /dev/null $FILE

I'd say 0 points for UNIX knowledge, 10 points for coolnes.

I/O tuning for Nagios

Since the setup of our new Nagios Cluster (based on Linux-HA and DRBD) I hat a slight discomfort looking at the Network and Disk I/O rates of the System. We had about 10MBit/s network traffic between the Nodes. I was almost sure it was caused by DRBD, since Nagios generates many Files.

Yesterday I had some time for tuning our systems. After a bit of looking around I moved some files and the network and disk I/O usage dropped by roughly 70%!

"I/O tuning for Nagios" vollständig lesen

Leicht Überlastet

man beachte den unbedeutenden Peak

PS: der Graph ist von keiner mega monster Maschine, sondern von einem gut benutzten 2 CPU 1 HE großem Arbeitstier ...