Re: -F option, RAM usage, more...

When I used postgres on linux, I found the following happened when the
system failed in the middle of transactions:

* ext2 + fsync: file system screwed-up, db OK
* ext2 - fsync: much faster than above, file system screwed-up, db needed to
be restored sometimes
* reiserfs + fsync: as fast as ext2 without fsync, file system OK, db OK
* reiserfs - fsync: no noticeable difference in speed from above, file
system OK, db had to be restored *every time*

Now I use freebsd...Can't comment on the various configurations yet, but to
the folks concerned with memory issues, take note of this: freebsd manages
virtual memory and disk caches much better than linux. It will even kick
idle processes out of memory to make room for disk cache, something I never
saw when working with linux.


----- Original Message -----
From: "Mitch Vincent" <mitch@venux.net>
To: <pgsql-general@hub.org>; "Neil Conway" <nconway@klamath.dyndns.org>
Sent: Wednesday, October 04, 2000 5:40 PM
Subject: Re: [GENERAL] -F option, RAM usage, more...


> Hmm, it seems we all know just enough to be dangerous :-)
>
> I have seen many threads on the "to fsync() or not to fsync()" and
> overwhelmingly people have come out and said that to not fsync() is A Bad
> Thing(TM).  -- If Neil is right then it being bad or not is going to
depend
> very much on the filesystem (I think)...
>
> Now I'm pretty confused (as I'm sure others are) -- can someone that knows
> beyond a reasonable doubt beat us with a clue stick on this?  Are we
taking
> a huge risk if we use -F and disable fsync() or no?
>
> -Mitch
>