IBM Systems Magazine, Mainframe - November/December 2016 - L13
Today, our clients are running their critical
applications on Linux on z Systems. We have clients doing payments,
payroll, mobile banking, real-time analytics and data warehousing."
-Martin Schwidefsky, Linux on z Systems development, IBM Germany Research & Development
clients can use. We began
working with SUSE first and
then Red Hat. In April 2016,
Canonical's Ubuntu was made
available on z Systems.
The Linux team at IBM
concentrates on core elements,
such as device drivers and
compilers. SUSE, Red Hat and
Ubuntu put together all of
the moving parts and create
something usable by our clients.
The distributors focus on
different parts of the OS and
vary in their offerings. Red
Hat and SUSE have a select
set of packages. The Ubuntu
distribution offers one of the
largest collections of opensource packages.
ISM: How does KVM on z Systems
improve performance and flexibility?
MS: KVM has different
aspects: the kernel module, a
combination of the interface
driver and the kernel module to
provide a VM on Linux, and the
IBM KVM product.
IBM's KVM is an alternative
to our z/VM* Hypervisor, which
won't go away any time soon.
KVM and z/VM Hypervisor can
co-exist on the same system.
KVM allows IBM to expand
our audience for Linux on
z Systems and enables us to
attract new clients who already
have KVM installed or who lack
the necessary z/VM skills. If the
IT shop lacks z/VM skills, it's
easier to use KVM because it uses
z/VM Hypervisor still has an
advantage, particularly with the
I/O landscape because you can
have dedicated devices with the
guest. With KVM, only virtual I/O
exists right now.
IBM has optimized KVM to
run on z Systems to get the best
performance from the machine.
We also have a cloud offering
where you can integrate KVM
into the cloud.
ISM: What are some of the new
kernel versions that have been
MS: The kernel community
doesn't think of kernel releases
as you might have with a product
release. When a new piece of
code is ready, it's published for
review. If everyone is content
with the code, it's placed to be
picked up as part of the next
The distributions created
by our distributor partners
are probably more important.
Whenever we have a new
z Systems machine, we
provide support code for that
machine to our distributors to
be incorporated into the old
distributions. Many clients are
using an older version of the
kernel, so we backport the new
code so they can use it. The
institutional release becomes the
critical factor-not the kernel.
of z Systems
Linux installed on
their systems as
of 2Q 2016
ISM: Could you talk about kernel removal and why you would remove it?
MS: Large sections of code in the
kernel have fallen out of use. We
remove these to make the kernel
smaller and easier to handle.
For example, we've removed the
capability to compile a 31-bit kernel because all of the machines
now use a 64-bit kernel. The
64-bit kernel can still run 31-bit
ISM: What services/workloads will
be driving demand for Linux on
z Systems over the next several
MS: In the end, demand is driven
by whatever the client needs to do
with the platform. Certain trends
in the industry, such as blockchain, are becoming important.
Big data and analytics remain
important. Payroll applications
are critical for some clients.
If clients require changes,
we do so. You have to provide
new solutions that are ready to
be picked up by the client, but
you must also take care of client
Linux on z Systems NOVEMBER 2016 // 13
9/29/16 1:14 PM