
>On Fri, Aug 30, 2002 at 02:08:59PM -0700, Tyler Mitchell wrote:
>>
>> I know that I need to at least get some more understanding on the
process
>> that takes place.

>The problem is that PostgreSQL doesn't have a "read only" mode.  So
>you can't really do it this way.

Okay, that answers one of my questions, thanks Andrew. Is this something
that others may be interested in?  Is it realistic to ask that it be added
to the TODO list?
What kind of writes occur normally, how does file locking work.  Could you
direct me to other resources on this for postgresql?

>
>Is there a way to make a RAMDISK on Win32?  If so, Tom Lane's
>suggestion is probably the best one.  Set up a RAMDISK, put your data
>directory there, and presto.  Of course, that means you need enough
>physical memory to hold the database, which might cause problems.
>
>What about using the CD-ROM to copy a version of the database onto
>the hard drive?  You could delete it when your application shuts
>down, I guess; you'd still need that much free space for your db,
>though.

Yes, both good ideas, we've been kicking these around.  But we just wanted
to exhaust the possibilities before we "give in" :)

One more idea, is it possible to "fake" a read-write file system.  I.e.
supply the files that postgresql will be looking for? (I know it's a
stretch, but hey, this IS the "hackers" list)  :)

Thanks guys.



Fri, 30 Aug 2002 14:34:00 -0700
"Tyler Mitchell" <TMitchell@lignum.com>
Re: Running postgres on a read-only file system
On Fri, 2002-08-30 at 16:34, Tyler Mitchell wrote:
> 
> >On Fri, Aug 30, 2002 at 02:08:59PM -0700, Tyler Mitchell wrote:
> >>
> >> I know that I need to at least get some more understanding on the
> process
> >> that takes place.
> 
> >The problem is that PostgreSQL doesn't have a "read only" mode.  So
> >you can't really do it this way.
> 
> Okay, that answers one of my questions, thanks Andrew. Is this something
> that others may be interested in?  Is it realistic to ask that it be added
> to the TODO list?
> What kind of writes occur normally, how does file locking work.  Could you
> direct me to other resources on this for postgresql?
> 
> >
> >Is there a way to make a RAMDISK on Win32?  If so, Tom Lane's
> >suggestion is probably the best one.  Set up a RAMDISK, put your data
> >directory there, and presto.  Of course, that means you need enough
> >physical memory to hold the database, which might cause problems.
> >
> >What about using the CD-ROM to copy a version of the database onto
> >the hard drive?  You could delete it when your application shuts
> >down, I guess; you'd still need that much free space for your db,
> >though.
> 
> Yes, both good ideas, we've been kicking these around.  But we just wanted
> to exhaust the possibilities before we "give in" :)
> 
> One more idea, is it possible to "fake" a read-write file system.  I.e.
> supply the files that postgresql will be looking for? (I know it's a
> stretch, but hey, this IS the "hackers" list)  :)
The problem is every query wants to write the clog files.....




-- 
Larry Rosenman                     http://www.lerctr.org/~ler
Phone: +1 972-414-9812                 E-Mail: ler@lerctr.org
US Mail: 1905 Steamboat Springs Drive, Garland, TX 75044-6749


30 Aug 2002 16:37:22 -0500
Larry Rosenman <ler@lerctr.org>
Re: Running postgres on a read-only file system

> One more idea, is it possible to "fake" a read-write file system.  I.e.
> supply the files that postgresql will be looking for? (I know it's a
> stretch, but hey, this IS the "hackers" list)  :)

One of the tricks I use for diskless systems is to mount a ramdrive in a
union mount with a read only nfs mount.  This allows filewrites (to the
ram drive) but old originals are retrieved from the ramdrive.

This is done on FreeBSD, but is effective enough for getting a fully
functioning system (yes, Postgresql included).  Takes quite a bit of ram
though.


Perhaps there is a toolkit for windows that can do similar union mounts?


30 Aug 2002 17:43:29 -0400
Rod Taylor <rbt@zort.ca>
Re: Running postgres on a read-only file system