MySQL TCO Savings Calculator

MySQL created a TCO (Total Cost of Ownership) calculator showing how cheap MySQL is compared to Microsoft MSSQL and Sybase. Interestingly, the parent company Oracle remains out of this picture. I find that sad. Why not be open and let the customer decide? Either way, the savings of MySQL Enterprise Edition to MSSQL are shocking: MySQL TCO Savings Calculator. Add your grain of salt...

SOAP calls to Dell warranty site

Someone on the Dell PowerEdge mailing list has written a script that uses SOAP calls to query dell's warranty site. I'm sure it's helpful to someone else to know this.

Dell and Ubuntu Server Edition 11.10

Dell has released a statement about ubuntu 11.10 on Dell PowerEdge. Dell lists that Ubuntu should work where the previous versions also worked and is currently re-certifying most PowerEdge and PowerEdge-C servers. Check Canonical's hardware certification page for details. Also good to know is that OpenManage (OMSA) has been released for Ubuntu, although it is not officially supported.

pxeconfig to control PXE boot

pxeconfig:

With pxelinux, which is a derivative of syslinux, you can specify with a PXE configuration file how the node must boot. This configuration is placed in, e.g. /tftpboot/pxelinux.cfg directory

Sudoreplay Manual

Using sudoers in Linux to implement security is commonly done. Often administrators or operators allow themselves to 'sudo su -' to become root, without the need to know the root password. This is more comfortable as you don't need to type "sudo" in front of every command and your sudoers file becomes less exhaustive without the need to specify every command operators and sysadmins need.

However, enforcing everyone - even sysadmins - to prepend every command with "sudo" creates an audit trail when sudo logs to a file. This often required for compliancy reasons.

Now there is a command to playback sudo logs: Sudoreplay Manual.

Dell TechCenter: KVM Virtualization Made Easy

Dell TechCenter posted a very easy "how to get started" guide for KVM Virtualization that you may find useful if you're just getting started and know little or nothing about virtualization (in Linux or elsewhere). It's good for the basics.

Dell OMSA LivedDVD using CentOS

Dell TechCenter has released a LiveDVD image with OMSA to update firmware and BIOS on Dell hardware using a CentOS Linux distro.

Convert LiveCD ISO to PXE boot image

Howto convert a LiveCD image to a PXE Boot image. To convert the root of the ISO image to an NFS root and save on the RAM requirements when booting the image [RAM=2x(size of ISO in MB) + 60 MB], read this on PXE booting in general.

OMSA 6.5.1

Dell's released the latest version of OpenManage 6.5.1. It provides drivers, BIOS and firmware updates from Linux when running Dell PowerEdge hardware.

Removing Duplicate RPM Packages

My OEL4 servers still have duplicate RPM packages on 64 bit servers. Libs for 32 bit and 64 bit are often installed, even though they may not always be used. When upgrading a package, such as glibc, you run into the error that yum won't touch a package because it finds duplicates.

In this case you can try Removing Duplicate RPM Packages or remove a package using an explicit architecture tag:
yum package.{i386,i686,x86_64} such as yum remove glibc.i686.

If you have RHEL/OEL5 or higher, you're in luck because you can try to install the package yum-utils and run package-cleanup --cleandupes. yum-utils offer a bunch of useful tools for working with yum repos and so on.

Performance and Provisioning for Virtualized Oracle

EMC (VMware) has a great technical webcast and PDF online about Performance and Provisioning for Virtualized Oracle. I highly recommend you listen to it or read the sheets. Very informative if you want to use virtualized Oracle databases in a production environment.

Most set-ups of virtualizing Oracle databases on VMware fail because storage I/O becomes a bottleneck. It turns out, 50% of all surveyed set-up had storage configured wrong. The problems has to do with storage queues in the VM and subsequently on the ESX host. Additionally, vSphere 4.1 introduces features (SIOC) to optimize the I/O better to the SAN and para virtualized SAN drivers can further reduce latency and increase throughput.

Then the webcast also mentions Oracle's "native" NFS client (dNFS, PDF) inside the database kernel. This reduces the CPU overhead and latency normally observed on NFS client in the OS. By using Oracle's native NFS client, you can use shared storage in a grid computing environment more easily and the same way on Windows as well as Linux.

EMC VMAX SAN box has a feature called FAST VP which can optimize and distribute your storage needs from all-SAN to a mix of SSD, SATA and SAN where and when needed.

Very interesting read and much stuff to think about your own VMware set-up when using Oracle software.

Seeding Java Authorization and Authentication using /dev/urandom

We had a strange issue during Oracle WebLogic development yesterday. Setting up a secure connection between a client and the WebLogic Admin server took really long on our shiny new hardware (Dell R710) compared the older servers (Dell 2950). After we made sure everything was exactly the same, people started to blame C1 and C1E states and other powersave or cpu throttling measures. However, given the different in setup times (2-6 sec vs 50-90 sec), I suspected it to be something else. Throttling down from 2.23 GHz to 1.6 GHz cannot cause such a great difference. Or at least be unlikely.

Lo and behold, it turned out to be related to the seeding of the random number generator in Java. Normally this is linked to /dev/random but can be sped up by using /dev/urandom, which uses some entropy of your system. Still, the urandom device, while faster, still caused a 20-fold difference.

As a workaround, you can tell your JVM which seed generator to use and prevent JVM from waiting or looking or whatever it does. See also the JAAS Reference Guide for more information.

If you call your JVM with the command line switch
-Djava.security.egd=file:/dev/./urandom
it will go much speedier! And yes, there is a dot "." inside that path, in order to work around another bug. :)