[ovirt-devel] Memory stats in VDSM

[Tomáš Golembiovský]

Hi,

there is ongoing effort to change how VDSM collects information about
memory usage from guests. We used to use oVirt guest agent to get the
statistics about free memory, swap usage, etc. This is going to change
and we will use stats provided by VirtIO Balloon driver. [1] This should
not break MOM nor Engine (current or previous versions).

There is however small downside to this change. We will not be able to
fetch information about buffers and caches on Linux guests anymore
(mem_cached and mem_buffers in memoryStats). The corollary of this is
that free memory reported by Engine will also no longer include those
statistics and reported free memory will be really (only) free memory.

I now there will be mixed feelings about this and we would like to get
the information about buffers and caches back to the VDSM. Correctly via
balloon driver statistics. [2] This effort will however take some time.

    Tomas


[1] https://gerrit.ovirt.org/#/q/topic:memory-stats
[2] https://lists.nongnu.org/archive/html/qemu-devel/2017-08/msg05239.html

-- 
Tomáš Golembiovský <tgolembi at redhat.com>