Thread: Shared disk

Shared disk

From
Nageshwar Rao
Date:

Hi,

I would like to use shared disk for two Postgresql database. I mean that two Postgresql Database point to same $PGDATA directory. Is this possible in Postgresql Clarification is appreciated.

Thx

 

Re: Shared disk

From
Alvaro Herrera
Date:
On Thu, Dec 09, 2004 at 09:02:51AM +0530, Nageshwar Rao wrote:

Hi,

> I would like to use shared disk for two Postgresql database. I mean that two
> Postgresql Database point to same $PGDATA directory. Is this possible in
> Postgresql

Not at all.  You can of course create two databases within one cluster
(== postmaster), but you can't have two clusters in the same data area.

--
Alvaro Herrera (<alvherre[@]dcc.uchile.cl>)
"El sentido de las cosas no viene de las cosas, sino de
las inteligencias que las aplican a sus problemas diarios
en busca del progreso." (Ernesto Hernández-Novich)

Re: Shared disk

From
Doug McNaught
Date:
Nageshwar Rao <NageshwarR@PLANETASIA.COM> writes:

>    Hi,
>
>    I would like to use shared disk for two Postgresql database. I mean
>    that two Postgresql Database point to same $PGDATA directory. Is this
>    possible in Postgresql Clarification is appreciated.

No, this is not possible.

You may want to look at replication solutions such as Slony-I.

-Doug

Re: Shared disk

From
Christopher Browne
Date:
A long time ago, in a galaxy far, far away, NageshwarR@PLANETASIA.COM (Nageshwar Rao) wrote:
> I would like to use shared disk for two Postgresql database. I mean
> that two Postgresql Database point to same $PGDATA directory. Is
> this possible in Postgresql Clarification is appreciated.:p>

No, you can't do this, at least not if you expect the two database
processes to run at the same time.

There are High Availability systems that work in somewhat this
fashion; both servers access the same disk.  But with a very precise
set of semantics:

  -> The database filesystem is only mounted on one system at a time

  -> The database process only runs on one system at a time

  -> If the HA system detects that one server has gone down, it
     "kicks" it to keep it down, and starts up services on the other
     one.
--
select 'cbbrowne' || '@' || 'gmail.com';
http://linuxfinances.info/info/postgresql.html
You don't *run* programs on Ultrix.
                - Mark Moraes
Right, you chase them.
                - Rayan Zachariassen

Re: Shared disk

From
Christopher Browne
Date:
No, you can't do this, at least not if you expect the two database
processes to run at the same time.

There are High Availability systems that work in somewhat this
fashion; both servers access the same disk.  But with a very precise
set of semantics:

  -> The database filesystem is only mounted on one system at a time

  -> The database process only runs on one system at a time

  -> If the HA system detects that one server has gone down, it
     "kicks" it to keep it down, and starts up services on the other
     one.
--
select 'cbbrowne' || '@' || 'gmail.com';
http://linuxfinances.info/info/postgresql.html
You don't *run* programs on Ultrix.
                - Mark Moraes
Right, you chase them.
                - Rayan Zachariassen