Re: Oracle9i and 8GB RAM on Win2k Adv. Srv.

"Dan Yusuph" <oradba_at_mail.kz> wrote in message news:150627cb.0301212107.280ab975_at_posting.google.com...
> "Richard Foote" <richard.foote_at_bigpond.com>
> wrote in message news:<sybX9.29588$jM5.76263_at_newsfeeds.bigpond.com>...
> > "Neil" <hi_neil_at_yahoo.com> wrote in message
> > news:85c46a2b.0301191016.75a38874_at_posting.google.com...
> > > Thanks guys,
> > > for all your help and suggestions.
> > >
> > > As soon as I make some progress to get 8GB RAM working on 9i rel. 2 .
> > > I will post it.
> >
> > Hi Neil,
> >
> > I don't have your original post but I do know how (finally) to get more
than
> > 4GB on MS Adv Server/.NET on 9i Rel 2. It took a little while but we got
> > there.
> >
> > Email me for all the juicy details.
> >
> > Cheers
> >
> > Richard

>

How can I refuse a smile (or the emails I've received privately)

Now confession time. When we initial had a go at making full use of our 16GB of RAM on a .NET box, we made a few silly mistakes and a few not so silly mistakes but eventually we got there. This is pretty well all documented in the Getting started on Windows manual so have a good look there. There was also a white paper on OTN but bugger me if I can now find it.

Anyway, basic steps are as follows (assuming appropriate O/S and memory):

1. Make sure you have the /PAE flag in your boot.ini. A problem we had was also having the /3GB switch, getting rid of it made the thing work.
2. Make sure the USE_INDIRECT_DATA_BUFFERS parameter is set to TRUE
3. Size the AWE_WINDOW_MEMORY registry parameter appropriately. This is the tricky bit. The purpose of this is to determine how much memory to allow for the Buffer Cache *below* the 3GB virtual address space and from which to access the extended memory. Note that *only* Buffer Cache buffers are allow "above" this 3GB limit and into the AWE buffer space. Note (hopefully obviously) that the larger the AWE_WINDOW_MEMORY, the better the performance but if you set it too big, you might not allow enough memory for everything else (and that's *everything* else, the rest of the SGA, all the PGAs, stack space, etc). It's a trade off. It's also a problem in getting all this to work in that if you make it too small (a mistake we kept making), the thing won't work. The minimum value for this is as follows:

(4096 * DB_BLOCK_SIZE * _DB_BLOCK_LRU_LATCHES) / 8 The default is 1GB, but we wanted to size this initially as small as possible to allow maximum memory for all our connections. Note that 8i had no such minimum size restrictions.

In my opinion, this limit of 3GB for non database buffer space is a serve restriction with all this. MTS and ORASTACK are options we may need to look at.

4) Size the Buffer Cache as required (and go into the realms of the unknown for 32bit windows). Make sure you do *NOT* use the new dynamic cache parameters DB_CACHE_SIZE (or any of the others) and stick with our old friend DB_BLOCK_BUFFERS. It will not work with the new parameters.

Word of warning here. Making anything *too* big in Oracle is never a good thing and so it is here. Poor DBWR is particular can have a hard time of it satisfying requests so I would strongly recommend close monitoring and tuning when attempting to implement this. Having to map and unmap blocks from the 2 different memory regions comes at a cost, but not (hopefully) as high a cost as a physical I/O.

Follow the above and hopefully you'll get it all to work as well.

Good Luck

Richard Received on Wed Jan 22 2003 - 08:37:32 CST