+1 for atop. Be sure to adjust the sampling interval so it suits your
needs. It'll tell you what caused the spike.
Alternatively you could probably use sysdig, but I expect that'd result in
a fair performance hit if your system is already struggling.
On 14 February 2018 at 08:15, Gunnar "Nick" Bluth <gunnar.bl...@pro-open.de>
> Am 06.02.2018 um 15:31 schrieb Thomas Güttler:
> > Am 05.02.2018 um 14:26 schrieb Andreas Kretschmer:
> >> Am 05.02.2018 um 14:14 schrieb Thomas Güttler:
> >>> What do you suggest to get some reliable figures?
> >> sar is often recommended, see
> >> https://blog.2ndquadrant.com/in-the-defense-of-sar/.
> >> Can you exclude other reasons like vacuum / vacuum freeze?
> > In the current case it was a problem in the hypervisor.
> > But I want to be prepared for the next time.
> > The tool sar looks good. This way I can generate a chart where I can see
> > peaks. Nice.
> > .... But one thing is still unclear. Imagine I see a peak in the chart.
> > The peak
> > was some hours ago. AFAIK sar has only the aggregated numbers.
> > But I need to know details if I want to answer the question "Why?". The
> > peak
> > has gone and ps/top/iotop don't help me anymore.
> > Any idea?
> I love atop (atoptool.nl) for exactly that kind of situation. It will
> save a snapshot every 10 minutes by default, which you can then simply
> "scroll" back to. Helped me pinpointing nightly issues countless times.
> Only really available for Linux though (in case you're on *BSD).
> Best regards,
> Gunnar "Nick" Bluth
> Mobil +49 172 8853339
> Email: gunnar.bl...@pro-open.de
> In 1984 mainstream users were choosing VMS over UNIX.
> Ten years later they are choosing Windows over UNIX.
> What part of that message aren't you getting? - Tom Payne