Re: Oracle 11.2 on AIX 7.1 JFS2 mount options

Hey Martin,
well let's say it this way - i worked way too many years with this crappy OS (e.g. USLA heap, dropped or hung TCP/IP packets in stack, wrong getrusage(), etc.) for Oracle databases and still need to nowadays from time to time ;-)

> Still open questions: Is this SAP Note's advice still valid for AIX 7.x ?

Please forget the SAPnote and read the mentioned paper or let me quote the corresponding part from it: "AIX 6.1 and AIX 7.1 combined with Oracle >= 11.2.0.2 introduced a new open flag O_CIOR which is same as O_CIO, but this allows subsequent open calls without CIO. The advantage of this enhancement is that other applications like cp, dd, cpio can access database files in read only mode without having to open them with CIO. Starting with Oracle 11.2.0.2 when AIX 6.1 or AIX 7.1 is detected, Oracle will use O_CIOR option to open a file on JFS2. Therefore you should no longer mount the filesystems with mount option –o cio."

> My big question is if O_CIOR really does the same per file as O_CIO does for the file system.

I_CIO is a flag that is set as a parameter by calling fopen() and in the old days (before O_CIOR) this caused issues if your database has opened the files with the I_CIO flag (due to filesystemio_options=setall) and you did not mount the filesystem with the "cio" option. In consequence third party tools (like cp or mostly flat file copy / backup tools) tried to open these files without the I_CIO flag and failed. This "mixed" fopen() mode works nowadays with the flag O_CIOR - so no need for mount option "cio" anymore. You also can truss it :-)

Best Regards
Stefan Koehler

Freelance Oracle performance consultant and researcher Homepage: http://www.soocs.de
Twitter: _at_OracleSK

> Martin Klier - Performing Databases GmbH <martin.klier_at_performing-db.com> hat am 21. Dezember 2016 um 21:29 geschrieben:
>
> Stefan, sometimes you are frightening me. :)
> Thanks, will look that paper up.
>
> Still open questions: Is this SAP Note's advice still valid for AIX 7.x ?
> My big question is if O_CIOR really does the same per file as O_CIO does for the file system. The SAP note seems to tell otherwise.
>
> But if I am not allowed to set CIO any more, how can I get concurrent WRITE capability?
>
>
> --
> Martin Klier | Performing Databases GmbH
> Managing Partner | Senior DB Consultant
> Oracle ACE
>
> martin.klier_at_performing-db.com | http://www.performing-databases.com

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