> > This behavior raises the question about file system usage in Postgres. Many
> > databases, such as Oracle, create table space files and operate directly on the
> > raw blocks, bypassing the file system altogether.
>
> OK, we have considered this, but frankly, the new, modern file systems
> like FFS/softupdates have i/o rates near raw speed, with all the
> advantages a file system gives us. I believe most commercial dbs are
> moving away from raw devices and toward file systems. In the old days
> the SysV file system was pretty bad at i/o & fragmentation, so they used
> raw devices.
I'm starting to like the idea of raw FS for a few reasons:
1) Considering that postgresql now does WAL, the need for a logging FS
for the database doesn't seem as needed (is it needed at all?).
2) Given the fact that postgresql is trying to support many OSs,
depending on, for example, XFS on a linux system will cause many
problems. What about solaris? How about BSD? Etc.. Using raw db MAY be
easier than dealing with the problems that will arise from supporting
multiple filesystems.
That said, the ability to use the system's FS does have it's advantages
(backup, moving files, etc).
Just some thoughts..
- Brandon
b. palmer, bpalmer@crimelabs.net
pgp: www.crimelabs.net/bpalmer.pgp5
