Re: Database Block Size

On Tue, 17 Oct 2000 10:27:18 -0400, Walter T Rejuney <BlueSax_at_Unforgetable.com> wrote:

>
>Is there any file that I can look at or any command that I can issue which
>demonstrates the 8K block size? I'm starting to get convinced by this
>argument, but I need a little bit better authority then just saying "I
>read on USENET that....".

Unfortunately no. I've found that reading the system defaults in the *.h library (/usr/include/sys in many systems) usually gets me there.

But bear in mind that doing things like adding Veritas I/O or using a EMC may change this! You basically need to dig into the man pages and the product base that is being used in the site to find this out.

Very few UNIX makers will give you a clear answer. Mostly because they don't want to commit themselves to any number, given that they allow Veritas, EMC and others to tweak their low level "cooked" I/O.

There are a few UNIXes that will have specific commands to tell you this. IIRC, AIX was one of them. Can't remember about HP and Dynix, dunno about Solaris.

>
>Also, if this is true, why is it never mentioned in any of Oracle's
>documentation? Or is it there and I've just never seen it.
>

It is there ( the UNIX block size, not the specific 8K). But out of context. Ie, there is no clear distinction between statements like "2K for OLTP, 16K for warehouse", which really apply to sites using raw, and the use of the standard I/O UNIX size for cooked.

>
>By the way, what is the corresponding block sizes for WinNT, Win2K and
>Win98? So far the only platforms I have had to create databases for are
>Windows and Unix.
>

native NT and 2K: 4K is a safe value. Again, if you're using specific I/O drivers to interface to EMC boxes and stuff like that, then you gotta be careful and dig into doco.

W98 and ME: dunno, and I don't think anyone should attempt to run a production server on one of these.

Cheers
Nuno Souto
nsouto_at_nsw.bigpond.net.au.nospam
http://www.users.bigpond.net.au/the_Den/index.html Received on Wed Oct 18 2000 - 04:38:17 CDT