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Friday, October 27, 2006

my everyday struggles with noac……….

"noac" is a mount attribute that disables attribute caching on the client side. If you are on RAC this option is mandatory for mounting shared files with NetApp. I have proved several times now through several tests that our performance is 3 to 4 times slower with the noac option as opposed to mounting the files without noac. Oracle does support RAC on NetApp – and NetApp requires the noac option for RAC. The bottom line the database is suffering from performance problems due to this option ; the current version is SLES 8 and Oracle 9i. NetApp claims that with SLES 9 we should not have any problems and Oracle says Oracle10g On Solaris should not pose any problems. ….well, I will have to see to believe now …we are in the process of a couple of migration tests to get past this problem

more on NetApp and RAC can be found on the below link


  • i have had similar issues in the past.
    just wanted to drop a quick comment here though its late :(

    In AS2.1 and RHEL3.0 (pre QU3), we have to use "nointr" and "noac" options.

    In SLES9 , we should use "actimeo=0" instead of "noac" option.
    Not sure about SLES 8 though. wud like to see an update to your post based on your migration results.

    By Blogger Arunkumar, at 10:19 AM  

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