Re: oracle on sun solaris

hopehope_123 wrote:

>
> 1. What file system to choose? UFS , Veritas or raw device?

UFS stands for Unbelievably Fouled-up System. Steer clear from it. Veritas with Quick I/O is the best option.

>
> 2. If i choose ufs or veritas , should i use direct_io or not? Since
> parallel query bypasses the sga , and directIO bypasses the page
> cache , using buffered io is better .

The two are not related. Parallel query used Oracle's direct read which, in the Oracle world, means read into the PGA, not the SGA. Direct I/O bypasses system buffer cache, thus avoiding double buffering and reads directly into the user buffer, which can also be SGA. The problem lies in the fact that all modern Unix systems have dynamic I/O buffers. If your processes tend to allocate large sort/hash areas, like DW processes do, you might cause problem with paging/swapping. Get the latest Cockroft's book and see what can you do about that. On the other hand, buffered file system layer usually does asynchronous prefetch, which can be quite handy for the database that is mostly used for reading. Ask Oracle to give you references from the companies of the similar profile to your (aka "competition") on the similar hardware. Then call them and check the references.

>
> 3. How can i coose the strip size of the raid?

By reading articles from http://www.baarf.com.

-- 
Mladen Gogala
http://www.mgogala.com