Appendix A. The Virtual Host Metrics Daemon (vhostmd)

vhostmd (the Virtual Host Metrics Daemon) allows virtual machines to see limited information about the host they are running on. This daemon is only supplied with Red Hat Enterprise Linux for SAP.

In the host, a daemon (vhostmd) runs which writes metrics periodically into a disk image. This disk image is exported read-only to guest virtual machines. Guest virtual machines can read the disk image to see metrics. Simple synchronization stops guest virtual machines from seeing out of date or corrupt metrics.

The system administrator chooses which metrics are available for use on a per guest virtual machine basis. In addition, the system administrator may block one or more guest virtual machines from having any access to metric configurations.

Customers who want to use vhostmd and vm-dump-metrics therefore need subscriptions for "RHEL for SAP Business Applications" to be able to subscribe their RHEL systems running SAP to the "RHEL for SAP" channel on the Customer Portal or Red Hat Subscription Management to install the packages. The following kbase article in the customer portal describes the setup of vhostmd on RHEL: https://access.redhat.com/knowledge/solutions/41566