On Monday, 08/03/2020 at 04:00 GMT, Mariusz Walczak <blanc...@gmail.com> wrote: > How to properly use zVM and zLinux virtualization technology to increase > Openshift Cluster capacity from 12 vCPU to 24 vCPU, without degrading > performance. Which of the approaches below is correct ? > - to have 6 Worker Nodes (zLinux), 4 vCPU each ? > - to have 1 Worker Node with 24 vCPU ? (lets forget about single point of > failure for now)
6 worker nodes with 4 vCPUs. > > I'm trying to understand - does it make any difference which option I take > ? At the end its vCPUs fighting for real CPU time on CEC (and for option 2 > I avoid OS overhead and OS management) z/VM itself doesn't care overly much, but the guest will. With too many virtual CPUs, it can't make forward progress on all of its CPUs at (approximately) the same time. That means threads wait longer for other threads to complete due to "dispatch latency". Linux can make better scheduling decisions if he has a better picture of processing capability. You convey that to him by managing the number of virtual CPUs. Alan Altmark Senior Managing z/VM and Linux Consultant IBM Systems Lab Services IBM Z Delivery Practice ibm.com/systems/services/labservices office: 607.429.3323 mobile; 607.321.7556 alan_altm...@us.ibm.com IBM Endicott ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www2.marist.edu/htbin/wlvindex?LINUX-390
