Linux + z/VM = Linux on Z
Demystifying Linux on Z
Linux on Z is Linux compiled for the IBM Z s390x architecture. Red Hat Enterprise Linux and SUSE Linux Enterprise Server are the principal distributions available for this platform.
For IBM Mainframe sites, an important advantage is the ability to evaluate Linux on existing infrastructure without an initial hardware investment. A z/VM LPAR hosts virtual machines that IPL Linux kernels from DASD volumes.
z/VM can be compared functionally with other hypervisors, although its architecture and operational model remain specific to IBM Z. Production deployment may then use Integrated Facility for Linux (IFL) processors or dedicated LinuxONE systems.
For system administrators, the main differences between Linux x86 and s390x concern device drivers and boot management: GRUB on x86 and zipl on s390x.
For low-level developers, CPU byte order is another difference: x86 is little-endian, while s390x is big-endian. Beyond these platform-specific elements, Linux administration and applications remain based on the same Linux concepts and tools.
HH&S was already documenting Linux on S/390 in 2001 in this historical article.
Our added value
Introducing Linux on Z into an information system raises organizational as well as technical questions, particularly around cooperation between Open and Mainframe teams.
- How should responsibilities be presented to Open and Mainframe teams?
- Which RACI model should cover build, run, maintenance and support for both the z/VM hypervisor and the Linux operating system?
- Which skills and training are required?
- How should existing installation automation—portals, technical repositories, Jenkins, VMware APIs, Ansible and Kickstart—be adapted to z/VM and Linux on Z?
Based on its experience with Linux on Z implementation projects in large organizations, HH&S provides consulting and technical expertise on these subjects.