Wednesday, December 13, 2017

Performance: Network Storage Protocols in a KVM Environment

Our performance group has published a new white paper titled "Network Storage Protocols in a KVM Environment - NFS/SMB/iSCSI Report" (.pdf and .html).

Abstract: 
"iSCSI, NFS, and SMB protocols provide access to storage resources via a TCP/IP network. While iSCSI provides block device access, NFS and SMB are file-level access protocols. In cases where the devices are mounted on the KVM host (as in our case) they could be functionally considered as equivalent when utilized for KVM guest device attachment with image files."

Tuesday, December 12, 2017

Monday, December 4, 2017

Getting Started: Instructions for Ubuntu 16.04 to 17.10 added

Instructions for Ubuntu 16.04 to 17.10 were added to the "Getting Started with KVM on Z" series.
See here for the entry page.

Friday, December 1, 2017

New "Getting Started" Series

A new series of articles will provide step-by-step instructions on how to setup and run KVM on Z. It will be updated continuously for new Linux distributions.
See here for the entry page.

Monday, September 11, 2017

DataCenter Insider Article

See here for an article (in German) in DataCenter Insider about KVM on z's history, usage concepts, support and z14 features.

Tuesday, September 5, 2017

QEMU v2.10 released

QEMU v2.10 is out. See here for a detailed list of all changes related to IBM Z. Here are some of the highlights from a KVM on z perspective:
  • z14 CPU model
    Provides base support for all of the features introduced with the z14's new processor generation.
    See this previous blog post for details.
  • Emulated 3270 Device
    This implementation has been tested with x3270 only. Your mileage with other clients might vary. For practical matters, the sclp console remains to be the recommended terminal type for KVM guests on z.
    To configure a 3270 device on a guest accessible on localhost at port 23, add a serial TCP device as follows to the <devices> element of the respective guest's XML:
    <serial type="tcp">
    <source mode="bind" host="0.0.0.0" service="23"/>
    <protocol type=’tn3270’/>
    <target type=’x-terminal3270’ console=’on’/>
    </serial>
    See here for further hints on how to use.
  • Bootparameter Support
    Until now, when a guest had multiple kernels to boot with, one had to change the default kernel in /etc/zipl.conf and re-run zipl to boot with a different kernel next time.
    With this feature, we now support option -L in the chreipl command from the s390-tools package, which allows to switch to a different boot option dynamically, e.g. using
  • $ chreipl ccw -d 0.0.1234 -L 2
    However, if somebody has set a new default kernel that does not boot, this will not help, since the guest will not start anymore in the first place.
    However, with the newly introduced attribute loadparm, one can switch to a different (working) kernel within the host in a guest's XML:
    <disk>
    ...
    <boot order='1' loadparm='2'>
    </disk>
    Notes:
    • chreipl changes will no longer be effective after the respective guest has been powered off.
    • The loadparm attribute became available with libvirt v3.5 or higher.