Re: Raw VS. Cooked

Michael Segel wrote: > snip... > end snip > > > > Simple. > Raw devices have less IO overhead than Cooked devices hence better > performance. > Now with AIX, IMHO, the best thing to do is to use LVM to create *file > systems* > just don't mount them. Then create your syns to Informix. I would *not* do that. It is too dangerous. Somebody might mount the filesystem use it and such destroy your database !!!And there is no reason to do that. > > > Oh and remember to off set your entry into the raw space by 4 pages? At > least enough room > to let AIX write the filesystem information. This will allow you to grow > the file systems as needed. Just create a logical volume (without filesystem !!!). For security reasons specify an offset of 4k for the informix chunk (this leaves the logical volume descriptor intact).If you like or need to you may increase the logical volume size at any time. But take into account, that Informix does not allow you to extend the size of a chunk. All you can do with the increeased size is to place another chunk behind the first one into the same logical volume (using offset). In this case you should know that due to the addressing used by Unix for the time being (4 byte signed integers), offset + size must not be greater than 2 GB. > > > -HTH > Mikey Helmut Leininger Bull AG /Vienna Unix Support Email: Helmut.Leininger@bull.net