Author Archives: azouhr

Online Enabling new DASD from a Linux LPAR on System z

When running a mainframe, there are reasons why you you want to add new control units and DASD disk devices. Assuming that you already added the hardware configuration to the system, you will find that a still running LPAR with … Continue reading

Posted in block devices, DS8000, Mainframe, Uncategorized, z Linux | Leave a comment

Port Forwarding with xinetd

In some network environments, where for example administration lans or some private lans are deployed, it might still be necessary to access a specific port of a machine inside that lan from the outside. Commonly, you would have to access … Continue reading

Posted in Networking, openSUSE, xinetd | Leave a comment

libvirt: chardev: opening backend “pty” failed: Permission denied

Recently I found myself in front of a strange problem that prevented me from creating new virtual machines with libvirt on KVM. Everytime I tried to create a virtual machine, I got a message similar to this: Error: internal error … Continue reading

Posted in KVM, libvirt | Tagged | Leave a comment

Persistent IUCV Network Devices

On mainframes, Inter User Communication Vehicle provides a means to exchange data between two guests in z/VM. Some time ago, this has been one of the preferred networking methods between two Users (virtual machines) on z/VM. From a linux perspective, … Continue reading

Posted in Mainframe, Networking, udev, z Linux | Tagged , , | Leave a comment

DRBD and Network Restarts

Using drbd as a simple and reliable alternative to distributed block devices is quite common. Especially in primary/primary mode, it provides the possibility to host block devices for virtual machines on two different hosts. However, there is one annoyance that … Continue reading

Posted in block devices, DRBD, Networking | Tagged | 1 Comment

Xen or KVM

Since little more than half a year, I am in the process of installing a new virtualization Platform. One of the hardest decisions to make was if we should use Xen or go with KVM. We already have Xen in … Continue reading

Posted in block devices, KVM, Networking, openSUSE, Xen | 1 Comment

Migrating a Xen VM to KVM on openSUSE

Xen and KVM are the two major virtualization techologies that are freely available on linux. Although they are quite comparable performance wise, it still may be interesting to convert a Xen virtual machine to a KVM virtual machine. Xen and … Continue reading

Posted in KVM, openSUSE, Xen | Leave a comment

Xen and serial console over IPMI (SOL)

Recently I had to configure a serial over lan (SOL) console on a bigger Supermicro server (2042G-TRF for those who are interested) that should run Xen. This turned out to be not too easy and several issues had to be … Continue reading

Posted in IPMI, openSUSE, SOL, Xen | 3 Comments

iTunes on openSUSE 11.4

In order to use iTunes University, I had to install iTunes on my notebook that is running openSUSE 11.4. It is quite easy to get some old version of iTunes from http://www.oldapps.com/itunes.php but trying to install it on a 64bit … Continue reading

Posted in iTunes, openSUSE, wine | 3 Comments

Simple udev Manipulations

When discovering the /sys file system, one can find quite a number of tunables that look interesting and really have effect on system behavior. Especially when experimenting with different values of read ahead for block devices or e.g. setting the … Continue reading

Posted in block devices, Hardware, openSUSE | Leave a comment