Re: Enable 32K Block in 8K Block DB

From: Howard J. Rogers <hjr_at_dizwell.com>
Date: Mon, 29 Mar 2004 15:23:25 +1000
Message-ID: <4067b2cf$0$15062$afc38c87@news.optusnet.com.au>

"Daniel Morgan" <damorgan_at_x.washington.edu> wrote in message news:1080537417.493976_at_yasure...

> > HJR
>
> I agree with one caveat. IIRC AIX 5L allows for other block sizes
> up to 256K. You must check with your SA to determine the block size
> before installing Oracle.
>
> Reference: http://hpcf.nersc.gov/vendor_docs/ibm/gpfs/am3admst09.html
>
> So while I believe you and Steve are correct on the Oracle basics. It is
> possible that the original 8K block size is correct Ok: Highly unlikely
> but possible.

No, it's a valuable caveat which I've mentioned before, and which it doesn't do any harm to mention again. The rule that says Linux and AIX = 4K and HP-UX and Solaris = 8K depends *entirely* on accepting the defaults when creating file systems. It is possible to change the *o/s block size* at the time of creating the file system, at which point you have another degree of freedom as it were.

But I would caution against using a 256K o/s block size (if such a thing were possible) because it isn't possible in Oracle (64K being the biggest one I ever heard of, and then only for some MVS, iirc -32K being the "normal" maximum). And if you can't persuade Oracle to use 256K blocks, then you've just broken Adams' first law.

Regards
HJR Received on Sun Mar 28 2004 - 23:23:25 CST