> -----Original Message-----
> From: Aage Johansen [mailto:aagjohan@...]
> Sent: Wednesday, June 27, 2001 2:24 PM
>

...

> Sean L. wrote;
> >...
> >.... The larger page size can also improve
> >raw database performance, but this also depends on a number of
> >factors including your server disk configuration.
>
> Could you expand on the specific "server disk configuration" subject ?
> What is of importance, and how?

I was wondering how long it would be before someone asked! Not bad, it
only took 7 hours! <grin>

Well, it starts with formating the disks with a sector size which is as
close as possible to your target database page size. A disk with
512byte sectors needs to perform 16 physical operations in order to
access/write a 8kb page. By the way, by default Win NT/2000 sector size
is 512bytes.

From there, the use of cached RAID controllers (with battery backup)
will make any disk setup fly. Activating the write-back setting on the
controller will allow for the OS to think that the write has taken
place, when in fact the controller has cached the update and will write
it out in a more efficient fashion. In fact, this type of setup would
allow for FORCED WRITE = ON to have almost no performance effect while
providing 99.999% data reliability. Please, please only set the
write-back setting if you have a *battery backed up cache*.

Also remember that there are a number of benefits to larger page sizes
which does not make the choice of page size not entirely a hardware
decision. Have a look #8 on this page
http://www.ibphoenix.com/ibp_scream.html

> > ...
> >Yes, set your sweep interval to 0 and let your nightly GBAK perform
> >the sweep/garbage collection at that time.
>
> Should this be:
> 1. Let gbak do the garbage collecting
> 2. Let sweep reset OldestTransaction
> or will gbak do-it-all?

Ooops, my bad. You're right.


Sean