Author Archives: azouhr

Multiple Linux Consoles in z/VM

The standard method to access z/VM is using a 3215 terminal with a terminal emulator. With linux, the x3270 package provides a free emulator for these terminals. One of the features of z/VM is, that you can define several consoles … Continue reading

Posted in 3270, Mainframe, SLES12, z Linux, zVM | Tagged , , , , , | Leave a comment

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