RE: 2 computers 1hd 2 postgres daemons. Is it possib le?

I think the problem is going to be how the two postgresql installations are
going to react to each other running on the same files at the same time.

I have a feeling there's going to be some horrible file locking but even
worse memory buffer problems lurking in there. If one backend writes to a
page, and the other also writes to the same page before the first has
flushed it's buffers, you'll end up with a corrupt table.

Peter

-- 
Peter Mount
Enterprise Support Officer, Maidstone Borough Council
Email: petermount@maidstone.gov.uk
WWW: http://www.maidstone.gov.uk
All views expressed within this email are not the views of Maidstone Borough
Council


-----Original Message-----
From: Clark, Joel [mailto:jclark@lendingtree.com]
Sent: Monday, October 16, 2000 9:58 PM
To: 'Tony Simopoulos'; Oscar Serrano
Cc: pgsql-interfaces@postgresql.org
Subject: RE: [INTERFACES] 2 computers 1hd 2 postgres daemons. Is it
possib le?


Through an NFS mount maybe?

-----Original Message-----
From: Tony Simopoulos [mailto:karkalis@earthling.net]
Sent: Monday, October 16, 2000 3:03 PM
To: Oscar Serrano
Cc: pgsql-interfaces@postgresql.org
Subject: Re: [INTERFACES] 2 computers 1hd 2 postgres daemons. Is it
possible?


a redundant, replicated, or parallel system (choose whichever adjective
befits your desires) is being developed.  check out
http://www.erserver.com/.

sharing a single disk is an O/S & hardware problem.  what is your intended
platform?

good luck,

tonys.

----- Original Message -----
From: Oscar Serrano <oserra@fondos.net>
To: Postgres interfaces <pgsql-interfaces@postgresql.org>
Sent: Monday, October 16, 2000 2:15 PM
Subject: [INTERFACES] 2 computers 1hd 2 postgres daemons. Is it possible?


> Hi men :-)
> Just one question for those of you who have spent many time with postgres.
> I want to create a load balancing and High Availability system with two
> servers.
> This two server have a common hard disk: A RAID 5 server connected to them
> by the LAN.
> I have a hardware machine (WSD+ from RADWARE) that manages the load
> balancing.
> I want to have, two servers, and two postgres installations, one in each
> server, but with a  common PGDATA directory in the RAID.
> So, if one of the servers crashes, people can still get the information
from
> the other server.
> Esentially, what I want is, two postgres (one in each machine) with a
shared
> PGDATA directory, and that both postgres can access and do Inserts in the
> tables, and when one postgres does an insert, the second sees what the
first
> has inserted.
>
> Thanks.
>
>
>