Tuesday, May 30, 2017

Migrating from KVM for IBM z to SLES12

In case you are contemplating a migration from KVM for IBM z to SLES12 SP2 or later, you might find the instructions published by SuSE here helpful.

Wednesday, May 10, 2017

QEMU v2.9 released

QEMU v2.9 is out. Here are the highlights from a KVM on z perspective:
  • Added support for virtio-crypto, providing a virtual crypto device as a front-end to the host's crypto capabilities on z Systems.
  • Added multiqueue support for virtio-ccw devices, improving throughput in presence of multiple processors.
  • Provided network boot enablement. See here for further details.

Tuesday, May 2, 2017

Linux kernel 4.11 released

Linux kernel 4.11 (available here) has been released, improving Kernel Samepage Merging (KSM) support for KVM on z:

KSM is an existing feature of the Linux kernel that allows the kernel to merge pages with identical content, indicated as MADV_MERGEABLE via madvise(), across different processes to save memory.
This z Systems specific extension improves the performance of userspace applications (e.g. QEMU) in case large amounts of empty/zeroed pages are merged.
This feature is disabled by default, enable as follows:

   $ echo 1 > /sys/kernel/mm/ksm/use_zero_pages