Re: Details after Load Peak was: OT: Performance of VM

From: Micky Gough <mgough(at)squiz(dot)net>
To: Gunnar Nick Bluth <gunnar(dot)bluth(at)pro-open(dot)de>
Cc: pgsql-performance(at)lists(dot)postgresql(dot)org
Subject: Re: Details after Load Peak was: OT: Performance of VM
Date: 2018-02-13 21:55:58
Message-ID: CAEaF9Mj8-kBKBArAU6Cafiw=FeUBVod__sJAOssLsBNpZcP9Bg@mail.gmail.com
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+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.

Micky

On 14 February 2018 at 08:15, Gunnar "Nick" Bluth <gunnar(dot)bluth(at)pro-open(dot)de>
wrote:

> 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
> RHCE/SCLA
>
> Mobil +49 172 8853339
> Email: gunnar(dot)bluth(at)pro-open(dot)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
>
>
>

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