Re: RAC & NFS noac mount option under AIX

Hi Thomas,

Have a look at this note:

Poor Performance of UTL_FILE on NFS Volumes (Doc ID 1534074.1)

    Remove the 'forcedirectio' and 'noac' parameters when mounting the NFS volume.

Note that
Bug 10189973 : SLOW PERFORMANCE WITH UTL_FILE WHEN WRITE TO NFS FILESYSTEM

was closed as “not a bug”

Cheers,

Leng.

> On 20 Aug 2021, at 2:10 am, Thomas Ranchon <thomas_at_ranchon.org> wrote:
>
> Hi,
>
> One of our production databases is a 2 node RAC extended cluster, OS is AIX 7.2
> (Oracle 18c that should be migrated to 19c by the end of the year)
> We are using 3 NFS mounts for :
> reading golden gate trail files (There is a golden gate Replicat running on this database)
> writing RMAN backups
> writing csv files with utl_filesand reading csv files with external tables
> Those three NFS are mounted on both RAC nodes.
>
> In production the golden gate and RMAN NFS mounts are mounted without the noac option, the NFS for csv files is mounted with the noac option.
>
> We are currently testing a migration from an old NAS to a new NAS for those 3 NFS mounts.
> For RMAN the documentation states that we should not be using the noac option, that's ok.
> For Goldengate the documentation states that we should be using the noac option. (Oracle GoldenGate Best Practice: NFS Mount options for use with GoldenGate (Doc ID 1232303.1)).
> I have not found anything related to the NFS mount option in a RAC database for reading and writing csv files using respectively external tables and utl_file.
> We have a process that is writing ~2500 csv files, on the old NFS with the noac option is was taking 3 minutes, with the new NFS with the noac option it's now taking more than 30 minutes, on the new NFS without the noac option it's taking 30 seconds.
> I have no metrics for the goldengate replication in our testing environment.
>
> Does anyone know if there is a mount option best practice for my third case? Should I consider those csv files as datafiles which means we should use the noac option.
>
> If noac is mandatory, I'll try to convince dba and storage teams to use ACFS instead of NFS. (We are currently using ASM for datafiles)
>
> Best regards,
> Thomas Ranchon
>

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