Re: IO Freeze ON RHEL 6.6 and hence high log file sync

Hey Purav,
what does the DM-multipather say? Do you have failing paths? Otherwise you can use blktrace to drill-down.

Best Regards
Stefan Koehler

Independent Oracle performance consultant and researcher Website: http://www.soocs.de
Twitter: _at_OracleSK

> Purav Chovatia <puravc_at_gmail.com> hat am 18. April 2018 um 19:25 geschrieben:
>
> We are on RHEL 6.6 running a 2-node Oracle 12c RAC.
>  
> All of a sudden, for 2-3 minutes, DATADG (asm diskgroup containing all data files) freezes for 2-3minutes with iostat showing 100% utilisation, very high svctm and very high write_await. But the r/s, w/s rsec/s and wsec/s is 0. Meaning no IO but still disk fully busy. So it’s like a freeze.
>  
> Has anybody experienced this and can somebody help as to what could be the reason? 
>  
> Transparent huge pages were not disabled and general huge pages were not configured. Now both done.
>  
> Many thanks

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