I know I am slightly late but I have been losing some sleep and lot of patience with my project(s) so bear with me : ). The question was " The ideal mounting option for ORACLE on JFS ? suggested is RBS & TEMP files : mincache=dsync, convosync=dsync DATAFILES & REDO files : mincache=direct,convosync=direct " Before jumping to answers definition of some terms used . CONVOSYNC : This option determines how synchronous writes are treated direct : Bypassing system buffer dsync : A write operation returns to the caller after the data has been transferred to external media, but the inode is not updated synchronously if only the times in the inode need to be updated MINCACHE : The mincache mount option determines how ordinary writes are treated. Can have the same values . I did some digging around and found some details First : The answer by Steve , Unless your 'db_block_size' is 8192 then you should use direct I/O for all Oracle file systems regardless of usage. Also because Oracle explicitly requests synchronous I/O whenever it opens its datafiles, it is the convosync mount option that counts, rather than the mincache one. Indeed, if you use 'convosync=direct, mincache=dsync' you'll get buffering for trace files or other stuff that might also reside on your Oracle file systems, which is probably what you want. I can't imagine any reason why you would want buffering for rollback segment datafiles, but assuming your block size is 8K, there is a weak argument for buffering temporary segment datafiles. Namely that temporary segment writes are invariably read again, and operating system buffering may save physical I/O on the reads. Oracle does not normally buffer temporary tablespace I/O and so with operating system buffering there is no buffering at all. However, if you machine is dedicated to Oracle and you are willing to allow Oracle to use the memory directly, then a better approach is to use the memory that might otherwise be used for operating system buffering of temporary tablespace writes to increase the 'sort_area_size' and thus avoid those writes entirely. Christian Bilien : The advice given looks good to me. Online JFS must indeed be separately purchased. In light of the above and my research , DATAFILES , RBS , TEMP : mincache=direct,convosync=direct,nodetainlog REDOLOG , ARCHIVE : mincache=dsync,convosync=dsync Any comments welcome . regards , RS __________________________________________________ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/ -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Raj Sakthi INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).