Re: [Users] Memory usage

----- Original Message ----- > From: "René Koch" <rkoch(a)linuxland.at&gt; > To: "Koen Vanoppen" <vanoppen.koen(a)gmail.com&gt; > Cc: users(a)ovirt.org > Sent: Wednesday, February 12, 2014 4:18:37 PM > Subject: Re: [Users] Memory usage > > On Wed, 2014-02-12 at 15:14 +0100, Koen Vanoppen wrote: > > In The GUI, it says it's using 25% of the memory. > > > I guess it's the real value, right? > The same happened for the memcached vm, someone reported to me - > negative value in REST-API, but correct graph in oVirt webadmin GUI. > > I fear I have no idea how this can happen - so maybe someone else can > help you troubleshoot this issue. > > > > > > > > 2014-02-12 15:10 GMT+01:00 Koen Vanoppen <vanoppen.koen(a)gmail.com&gt;: > > Thanks for the quick respons, but there is no memcached > > running on that VM. > > > > > > Kind regards > > > > > > > > 2014-02-12 15:06 GMT+01:00 René Koch <rkoch(a)linuxland.at&gt;: > > > > On Wed, 2014-02-12 at 14:55 +0100, Koen Vanoppen > > wrote: > > > Dear all, > > > > > > > > > When we monitor one of our machines, we noticed that > > there was one vm > > > that was constantly giving a error of memory usage. > > But when we took a > > > look at it, there is actually nothing wrong with it. > > Now we looked > > > furhter then that. We looked at the API of the > > machine and noticed > > > something very strange: > > > > > > <statistic > > > > > href="/api/vms/3b9aa245-75ff-42e8-b921-1c9ce61826bf/statistics/b7499508-c1c3-32f0-8174-c1783e57bb08" > > id="b7499508-c1c3-32f0-8174-c1783e57bb08"><name>memory.used</name><description>Memory > > used (agent)</description><values > > type="INTEGER"><value><datum>-944892806</datum></value></values><type>GAUGE</type><unit>BYTES</unit> > > > > > > > > > It's a negative... > > > > > > > > Do you have memcached running in this vm? > > > > I heard about this issue with memcached, but never > > tested memcached in > > my oVirt environment. You get the real usage value > > with > > memory.used = memory.installed + memory.used > > > > > > Regards, > > René > > > > > > > > > > > What could be the problem? > > > > > > > > > Kind regards, > > > > > > koen > > > > > Guys, these values are usually a result of overcommitment mechanism usage. For example, if KSM is effective, it will free a lot of memory pages, and total-free-committed becomes negative. This was reported in https://bugzilla.redhat.com/show_bug.cgi?id=977758 and the engine is using memFree reported by vdsm, which is more accurate. The API reports the old version due to backwards compatibility. Doron P.S. René- thanks for helping!