Re: Chunk Writes

> >Short of actually checking for disk name and then chunk offset within disk, > >there really is > >no way to ensure that writing is actually done completely in sequence across the > >entire > >disk. Even at that, when you consider logical volumes, disk arrays, disk > >sections, etc., I > >doubt that you could ever develop a method that would completely guarantee > >writes to occur > >in perfect order across all platforms. > > > Use 2Gb disks, 1 disk = 1 chunk = 1 dbspace. Also allows use > fragmentation across disks. You fragment across dbspaces and therefor > automatically across disks... > Yes, this is a valid strategy, at least in some cases. This is, however, a work-around, if you will. It requires that every dbspace be some multiple of 2 GB, or at least take up all of the disk if you use less than 2 GB disks. Maybe you have a rootdbs of 2 GB, but I don't need that much space and don't want to waste 95% of a disk to implement this work-around. As for fragmenting tables, that's another valid approach for some situations, but I doubt anyone wants to fragment a table listing the 50 states in the United States. This work-around also eliminates the possibility of using larger disks, which are becoming cheaper all the time. I would suspect that some time soon it will be as hard to find a new 2 GB disk as it currently is for a 40 MB disk. The point I was trying to make in the original response is that there is virtually no way for Informix to code the chunk write logic in such a way as to guarantee perfectly ordered writes across all platforms. Your approach will work, but it requires effort on your part to live within certain constraints, rather than having the DBMS figure it out on its own. Mark Collins mcollins@us.dhl.com Words that come to mean everything may finally mean nothing; yet their very emptiness may allow them to be filled with a mesmerizing glamour.