Oracle: Unbreak my Linux Heart

I'm no longer actively working with Linux although I use it privately. This was my work logbook during my job as a Linux Engineer and Architect for KPN Data Centers.  I'm keeping this as a log and note book. Who knows when it comes in handy although much will be outdated. If you find any good resources or more current howtos for what was written here, let me know!

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...

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 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 : 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

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

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 .

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.

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.

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 envi...

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 ...

The kind people of the German university of Göttingen have mirrored the Dell OMSA hardware and firmware repo for us. This way, we have a European mirror available that is also much faster than Dell's native server.

Dell has released version 6.5 of their OpenManage repository with firmware and BIOS updates as well as Linux monitoring of hardware found in Dell servers.

At work we are in the process of upgrading our VMware infrastructure to vSphere with new Vmax storage from EMC. One of the new features is VAAI , vStorage APIs for Array Integration. This abstracts certain aspects of storage to the SAN layer, where e.g. cloning can be a mere functional call that is then handled transparantly for the layer above. Yellow Bricks has a great post on VAAI sweetness collected from twitter and gathered or our convenience. Awesome!

Dell's OMSA is great for maintaining and updating a Dell server's firmware, if it works... Dell does a great job so far, but sometimes little quirks mess up small parts and suddenly OMSA will update all or nothing or only a few and then call it quits. pjwelsh has written a handy little summary of the various ways with which you can try to still get working, albeit manually: Failed BIOS update on Dell R710 with CentOS 5.5 solved! (Worked around, really)

Dell recently published a little more details about what Ubuntu Certified and Ubuntu Ready means . Even though Dell does not officially support Ubuntu, their hardware is labelled as Certified by Canonical and they can also provide with paid support for Enterprises that require it.

Besides having the option to download installation media from Oracle (for which you must register), you can use the Oracle Public Yum Server to get packages. For instance, to help solve ad-hoc dependencies. This alleviates you from the need to keep a local mirror available for all Linux releases.

Also found this great but slightly dated resource on Tuning Journaling File Systems . We had a crash of a VM recently with 3 million small files in a single directory. Tuning some mounts with noatime and dir_index helped a lot. Still tinkering with journaling options, though.