Re: [ovirt-devel] Memory stats in VDSM

> On 28 Aug 2017, at 13:37, Juan Hernández <jhernand(a)redhat.com&gt; wrote: > > On 08/28/2017 01:11 PM, Tomáš Golembiovský wrote: >> 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 > > Note that this information is currently reported by the engine REST API, so it is part of its contract. Removing it breaks backwards compatibility and causes a regression in this RFE: we can either declare it deprecated or temporarily report 0 until the support propagates into qemu-ga

I think best way forward is to just make it optionally available when ovirt-guest-agent reports it. I.e. users will get only part of the information when they run only qemu-ga, and that’s fine… > > [RFE] Report guests Buffered/Cached memory > https://bugzilla.redhat.com/1024010