Hide Forgot
Measure disk latency (read, write and flush) measured in ms for each virtual storage device in QEMU. Report this through qemu monitor and QMP for each virtual device (I'd suggest through query-blockstat) Use case: Allow a management system to poll QEMU via libvirt to record the read and write disk latency. This management system could use this information to report on potential bottlenecks or I/O issues experienced by virtual machines. Later this information would be used by Red Hat tools as part of an "SLA" management application to set thresholds and guaranteed resources for virtual machines. We have a very important virtualization systems management vendor lined up to provide RHEV and KVM support if we can provide this data
The decision is to use virDomainQemuMonitorCommand for RHEL6.2. We need to wait for python bindings for virDomainQemuMonitorCommand.
http://gerrit.usersys.redhat.com/#change,935
Andrew, qemu expose only accumulated disk latency for read, write and flush operations. So, I don't think that it's what you need to report in RHEV-M. But, except it qemu can report also the number of requests, so we can calculate the average latency. What do you think?
(In reply to comment #9) > Andrew, > qemu expose only accumulated disk latency for read, write and flush operations. > So, I don't think that it's what you need to report in RHEV-M. > But, except it qemu can report also the number of requests, so we can calculate > the average latency. > What do you think? Yes, that's correct we want the average.
removing libvirt dependency since we use libvirt_qemu.qemuMonitorCommand hack in rhel6.2.
Verified vdsm-108
Technical note added. If any revisions are required, please edit the "Technical Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. New Contents: No description necessary
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHEA-2011-1782.html