On Wed, Jul 5, 2017 at 5:57 PM Roy Golan <rgolan(a)redhat.com> wrote:
Hi all,
I would like to get feedback on $subject and see if I'm missing something.
The impact of this is simply less resource consumption and by that we can
support even greater number of hosts [1] and vms in the system.
If you think more relaxed statistics collection will affect a core flow
let me know - as far as I see I didn't spot anything critical.
The overhead of a cycle per host something like that: 2 roundtrips per
host in a cycle, (vm + host stats) and tons of memory allocation for char[]
-> json-> maps of maps -> VM/Vds statistics -> Maps -> serialiazing to
DB.
To minimize the effect of this change we can leave a call to 'list' verb
to at least detect vms existence in the same rate as today.
Pros
- Engine has rore resources to support more hosts/vms/other activities of
the engine
- Vdsm will have more resources as well (need to tweak vdsm to collect in
the same
frequency)
- less DB writes and reads, approx half of what the system will do in the
in its lifefpan (cause this is what is mainly does all the time)
Cons
- DWH/Dashboard will have less entries, I'm not sure what is graphical
affect given our hourly resolution (cmiiw here)
Why we have a monitoring interval at all? why not move the stats to events?
Vdsm should collect stats and send updates to engine, engine can do only
polling only if vdsm did not send any update in the last couple of minutes
or so.
Same for stats collected by collectd, we want to stream updates to engine
from
the host, no poll every host for the stats.
Nir