> Hmmm....why is it?
> I know the reason for having it's own partition is that Unix normally
> have this read ahead feature on its file system, thereby slowing
> down DBMS access, if the database is on the file system.
> Nowadays, I think you can disable that read ahead feature.  Is this normally
> the case?

If i still remember my dba days correctly (10 years ago, huhuhuh),
this is to compeletely bypass the OS caching.  DBMS caching + OS 
caching is just double work.  Plus  you have the overhead of
dealing with files (inodes, file offsets, etc).  The
dbms I dealt with actually read/writes PAGES directly with its
own caching manager...quite good though i never did manage
to test the raw partition though (we only had one machine).

Another ploy was the so-called "contigous" file where 
the file's inodes was created sequentially so a dmbs could
just assume and calculate file offsets from there.

the real plus IMHO is that it takes away the dbms from the
hands of programmers and Managers :-)  I've always like the
idea of the dbms as an abstract thing that you can only
access thru shared memory or a pipe or something...as 
far away as possible from the user, the better it is...
(just my opinion).

jondz

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