Re: Database cluster?

I've succesfully pacthed linux kernel 2.2.17 with DIPC and modified
postgresql's src  (src/backend/storage/ipc/ipc.c) to create distributed shm 
and sem.

The strategy is then to start a postgresql that creates shm and sem on ONE 
machine, then start other postgres on other machines on the cluster that 
create NO shared structures ( there is a command line flag to do this).

Than you can connect to any of the postgres on your cluster, for example: 
round robin.

Another issue are datafiles, GFS seems promising.
But postgresql uses fcnl, and GFS (globalfilesystem.org) doesn't support it 
yet.
A distributed filesystem with locking etc. is required, Ideas ?


Another issue is that DIPC doesn't have a failover mechanism.

This is a shared All approach, it's not the best, but probably it's the 
fastest solution (bad) to implement, with little modifications (4-5) lines 
to postgresql sources.

This system can give a sort of single-system-image, useful to distribute 
other software beyond postgresql.

Also Mariposa (http://s2k-ftp.cs.berkeley.edu:8000/mariposa/) seems 
interesting,
but it's not maintained and it's for an old postgresql version.

hoping for clustrering...
valter mazzola.


>From: Alain Toussaint <nailed@videotron.ca>
>To: PostgreSQL general list <pgsql-general@postgresql.org>
>Subject: Re: [GENERAL] Database cluster?
>Date: Thu, 30 Nov 2000 15:05:16 -0500 (EST)
>
> > Somebody mentioned the fact that postgres uses IPC for communicating
> > between processes. I think there are tools for clustering (I am not sure 
>if
> > Mosix supports transparently allowing IPC across nodes) which can work
> > around that.
>
>one of those tool is distributed ipc <http://wallybox.cei.net/dipc/> but
>it only work with Linux,AFAIK,the software there is just a patch to the
>Linux kernel and a daemon.
>
>Alain
>

_____________________________________________________________________________________
Get more from the Web.  FREE MSN Explorer download : http://explorer.msn.com