Re: Best File System Caching Method for Oracle on vxfs

Chuckster wrote:
>
> We are running 8.1.7.4 on Solaris 8 64-bit with Veritas Database Edition
> for Oracle 3.5MP1.
>
> What is the ideal file system caching policy? The options are "closesync
> direct dsync unbuffered tmpcache"
>
> This is your standard OLTP database. Or should the caching policy change
> depending upon the data there? ie: We have dedicated logging disks,
> dedicated temp and undo disks, and dedicated archive disks.
>
> Thanks for any info,
> CC
>
> -----------== Posted via Newsfeed.Com - Uncensored Usenet News ==----------
> http://www.newsfeed.com The #1 Newsgroup Service in the World!
> -----= Over 100,000 Newsgroups - Unlimited Fast Downloads - 19 Servers =-----

Unless your file system cache size is significantly larger than your oracle buffer cache (for example, 64bit OS running 32bit oracle), it would generally make sense not to use file system caching and allocate the memory saved to the oracle buffer cache.

the oracle buffer cache is more "intelligent" (when it comes to caching oracle blocks) because it is aware of things such as extent and segment boundaries.

'direct' is probably your best option (assuming you allocate the buffer cache appropriately and of course, test things out for adverse impacts)

hth
connor

-- 
=========================
Connor McDonald
http://www.oracledba.co.uk

"Some days you're the pigeon, some days you're the statue"