Re: DB Block Size in Linux

"Toby Brown" <toby_brown_at_optusnet.com.au> wrote in message news:2a84f50c.0401112041.4f55946f_at_posting.google.com...

> is there any benefit at all in using an 8k default db block size for
> an Oracle database on Linux, as opposed to a 4k block size? (of
> course, I ask this question with the Linux file buffer cache size (4k)
> in mind).
>

Toby, the Linux "file buffer cache size" is not 4K. The block size in Linux is highly dependent on the file system you're using. And even then, it's a tunable parameter.

And the caching for that file system in the Linux file system cache will be in logical blocks of 4K but MUCH larger than just 4K! In fact it is variable, depending on how much free memory your system has.

The most important thing you can do in Linux is match the database block size to what the file system block size is (or the other way around, if you have the luxury of creating the file systems from scratch).

The second most important thing is to use freshly made file system(s) to create the database files in. And reduce the amount of other files (non-db) kept on file system(s) to an absolute minimum or 0.

And if all else fails, use raw files rather than file system files. Then, the database will be the only user of those. And your upgrade to Oracle 10g will be so simple I can't even begin to describe how...

-- 
Cheers
Nuno Souto
wizofoz2k_at_yahoo.com.au.nospam