On 30.06.20 22:19, Tom Huegel wrote: > This has probably been discussed quite a bit but I wanted to ask for some > real user feedback. > > I have a customer that is interested a POC of z/VSE zLINUX VTAPE. > Unfortunately they do now have z/VM so the zLINUX would have to be in an > LPAR. So the question is 'do I gain/lose anything using KVM as the > hypervisor in the zLINUX LPAR?'.
As the zLINUX VTAPE application is just a Java applicaition that needs network and disk access I do not see a reason why it could not run in a KVM guest. I guess you have to ask yourself the question, will there be additional things that you might want to run on zLinux to support VSE. I think you got plenty of ideas in the recent mail threads. Then of course a hypervisor is going to help you. One nice thing with KVM is that you can actually add that later. So having one workload in an LPAR and then addding a KVM guest in the same LPAR to host another one would just work. Not that this is something that I would suggest. But the point is: no matter if you run Linux in LPAR or Linux under KVM. You always start with a Linux in LPAR and can then move to KVM or not. With some preplanning for the future you probably want to put the first workload also in a KVM guest to have equivalent management for all workloads (e.g. use CPU shares or capping). Regarding the downside, of course every hypervisor will add a small overhead. It starts with the memory footprint of an additional Linux kernel and it ends with the cost of virtualizing I/O. Does this matter for the vtape use case? Probably not. As an alternative that depends on your requirements regarding isolation you could put the workloads in containers. But this is only "nice" when the workload is already containerized. ---------------------------------------------------------------------- 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
