Re: troubleshooting slow I/O performance.
Date: Wed, 9 May 2018 21:48:05 +0200 (CEST)
Message-ID: <1489069188.416161.1525895286113_at_ox.hosteurope.de>
For example blktrace would help him in case of such IO outliers.
Independent Oracle performance consultant and researcher
Website: http://www.soocs.de
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> Mladen Gogala <gogala.mladen_at_gmail.com> hat am 9. Mai 2018 um 19:09 geschrieben:
>
> Hi Stefan,
>
> My understanding of the facts is the following:
>
> * SLOB established the fact that the average single block read takes 10ms to complete.
> * 10ms is not fast enough.
>
> From those two facts I conclude that the OP needs faster disks. It's as simple as that. The OP has also said that he has some flash disk groups which are much faster. Please let me know if my understanding of the facts is incorrect. Also, what insight can the OP gain from the rather strenuous exercise with blktrace and how can it help him?
>
> He used SLOB and has his results. My understanding is that SLOB results are taken as facts. So, we can take an average of 10ms for a single block read as a fact. If that is fast enough, all is well, nothing needs to be done. If not, the only way to fix things are faster disks. Did I go wrong somewhere?
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