patch posted on qemu-devel, reviewd, acked and merged into maintainer's branch: https://github.com/stefanha/qemu/commit/f050ea639522e9dd7e501ef285a2a12709b8726a
-- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1338957 Title: RFE: add an event to report block devices watermark Status in QEMU: New Bug description: Add an event to report if a block device usage exceeds a threshold. The threshold should be configurable with a monitor command. The event should report the affected block device. Additional useful information could be the offset of the highest sector , like in the query- blockstats output. Rationale for the RFE Managing applications, like oVirt (http://www.ovirt.org), make extensive use of thin-provisioned disk images. In order to let the guest run flawlessly and be not unnecessarily paused, oVirt sets a watermark and automatically resized the image once the watermark is reached or exceeded. In order to detect the mark crossing, the managing application has no choice than aggressively polling the QEMU monitor using the query-blockstats command. This lead to unnecessary system load, and is made even worse under scale: scenarios with hunderds of VM are becoming not unusual. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1338957/+subscriptions
