Thread: Re: Poatgresql database on more than one disk
Barry wrote: > Hi All, > > I am a newcommer to Postgresql, currently I am looking at moving > a Pick based application across to PostgreSQL. > > I am using RH Linux and Postgresql 7.3.6 > > The test system I am using has a 2 channel raid card with a disk pack > connected to each channel. The OS and Postgresql sits on its own internal > disk. > > I would like to be able to use one disk pack for development and the > other for end user testing / verification (the tape drive can only backup > one disk pack completely, not both) > > I have spent a fair amount of time researching how I can run two > databases, one on each disk pack but have not been able to find a > solution. > > Is it possible to configure Postgresql to have seperate databases > on seperate disks ? Not easily as will be with the Table Space feature that most probably will be present on 7.5 With 7.3.6 what you can do is move your db and create a link in the original place: -bash-2.05b$ oid2name All databases: --------------------------------- 17142 = kalman 19185 = photodb 27895 = empdb 1 = template1 17141 = template0 5776262 = logs -bash-2.05b$ pwd /var/lib/pgsql/data/base -bash-2.05b$ ll total 32 drwx------ 2 postgres postgres 4096 Feb 8 15:18 1 drwx------ 2 postgres postgres 4096 Feb 8 03:56 17141 drwx------ 2 postgres postgres 4096 May 25 19:37 17142 drwx------ 2 postgres postgres 8192 Feb 8 15:58 19185 drwx------ 3 postgres postgres 8192 May 16 02:46 27895 drwx------ 2 postgres postgres 4096 May 18 00:06 5776262 in my case if I want the database kalman to another disk what I have to do is: stop the engine, move the directory /var/lib/pgsql/data/base/17142 to the new location and create the link. With the same mechanism you can also place different tables in different disks. I hope this help you. Regards Gaetano Mendola
Gaetano Mendola <mendola@bigfoot.com> wrote in message news:<40B3E30C.3020408@bigfoot.com>... > Barry wrote: > > > Hi All, > > > > I am a newcommer to Postgresql, currently I am looking at moving > > a Pick based application across to PostgreSQL. > > > > I am using RH Linux and Postgresql 7.3.6 > > > > The test system I am using has a 2 channel raid card with a disk pack > > connected to each channel. The OS and Postgresql sits on its own internal > > disk. > > > > I would like to be able to use one disk pack for development and the > > other for end user testing / verification (the tape drive can only backup > > one disk pack completely, not both) > > > > I have spent a fair amount of time researching how I can run two > > databases, one on each disk pack but have not been able to find a > > solution. > > > > Is it possible to configure Postgresql to have seperate databases > > on seperate disks ? > > Not easily as will be with the Table Space feature that most probably > will be present on 7.5 > > With 7.3.6 what you can do is move your db and create a link in the > original place: > > -bash-2.05b$ oid2name > All databases: > --------------------------------- > 17142 = kalman > 19185 = photodb > 27895 = empdb > 1 = template1 > 17141 = template0 > 5776262 = logs > > > -bash-2.05b$ pwd > /var/lib/pgsql/data/base > > -bash-2.05b$ ll > total 32 > drwx------ 2 postgres postgres 4096 Feb 8 15:18 1 > drwx------ 2 postgres postgres 4096 Feb 8 03:56 17141 > drwx------ 2 postgres postgres 4096 May 25 19:37 17142 > drwx------ 2 postgres postgres 8192 Feb 8 15:58 19185 > drwx------ 3 postgres postgres 8192 May 16 02:46 27895 > drwx------ 2 postgres postgres 4096 May 18 00:06 5776262 > > > > > > in my case if I want the database kalman to another disk what I have to > do is: stop the engine, move the directory /var/lib/pgsql/data/base/17142 > to the new location and create the link. > With the same mechanism you can also place different tables in different > disks. > > I hope this help you. > > > Regards > Gaetano Mendola Works like a treat, thank you for your time. Barry
Could you just use the initlocation tool and specify the 'location'
parameter when creating the database?
-----Original Message-----
From: pgsql-general-owner@postgresql.org
[mailto:pgsql-general-owner@postgresql.org] On Behalf Of Gaetano Mendola
Sent: Tuesday, May 25, 2004 8:22 PM
To: Barry; pgsql-general@postgresql.org
Subject: Re: [GENERAL] Poatgresql database on more than one disk
Barry wrote:
> Hi All,
>
> I am a newcommer to Postgresql, currently I am looking at moving
> a Pick based application across to PostgreSQL.
>
> I am using RH Linux and Postgresql 7.3.6
>
> The test system I am using has a 2 channel raid card with a disk pack
> connected to each channel. The OS and Postgresql sits on its own internal
> disk.
>
> I would like to be able to use one disk pack for development and the
> other for end user testing / verification (the tape drive can only backup
> one disk pack completely, not both)
>
> I have spent a fair amount of time researching how I can run two
> databases, one on each disk pack but have not been able to find a
> solution.
>
> Is it possible to configure Postgresql to have seperate databases
> on seperate disks ?
Not easily as will be with the Table Space feature that most probably
will be present on 7.5
With 7.3.6 what you can do is move your db and create a link in the
original place:
-bash-2.05b$ oid2name
All databases:
---------------------------------
17142 = kalman
19185 = photodb
27895 = empdb
1 = template1
17141 = template0
5776262 = logs
-bash-2.05b$ pwd
/var/lib/pgsql/data/base
-bash-2.05b$ ll
total 32
drwx------ 2 postgres postgres 4096 Feb 8 15:18 1
drwx------ 2 postgres postgres 4096 Feb 8 03:56 17141
drwx------ 2 postgres postgres 4096 May 25 19:37 17142
drwx------ 2 postgres postgres 8192 Feb 8 15:58 19185
drwx------ 3 postgres postgres 8192 May 16 02:46 27895
drwx------ 2 postgres postgres 4096 May 18 00:06 5776262
in my case if I want the database kalman to another disk what I have to
do is: stop the engine, move the directory /var/lib/pgsql/data/base/17142
to the new location and create the link.
With the same mechanism you can also place different tables in different
disks.
I hope this help you.
Regards
Gaetano Mendola
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On Wed, 2004-05-26 at 07:24, Barry wrote:
> Gaetano Mendola <mendola@bigfoot.com> wrote in message news:<40B3E30C.3020408@bigfoot.com>...
> > Barry wrote:
...
> > > The test system I am using has a 2 channel raid card with a disk pack
> > > connected to each channel. The OS and Postgresql sits on its own internal
> > > disk.
> > >
> > > I would like to be able to use one disk pack for development and the
> > > other for end user testing / verification (the tape drive can only backup
> > > one disk pack completely, not both)
> > >
> > > I have spent a fair amount of time researching how I can run two
> > > databases, one on each disk pack but have not been able to find a
> > > solution.
> > >
> > > Is it possible to configure Postgresql to have seperate databases
> > > on seperate disks ?
> >
> > Not easily as will be with the Table Space feature that most probably
> > will be present on 7.5
> >
> > With 7.3.6 what you can do is move your db and create a link in the
> > original place:
...
> Works like a treat, thank you for your time.
You need to be aware that certain files in the top level of ${PGDATA}
(pg_clog/* and pg_xlog) are essential for reading your data and apply
globally to all databases. If pg_clog is destroyed, the database is
effectively destroyed too. It's not clear that your arrangements will
get that copied to tape.
You may also not be aware that simply dumping the files to tape is not
necessarily going to give you a consistent or recoverable database
unless you stop the postmaster first. pg_dumpall (or pg_dump for single
databases) can be used to dump transaction-consistent backups that
include every transaction completed at the time it begins to run; it is
also likely to take less space on tape than a dump of the raw database
files. If you recover a set of files that have been copied to tape by
an external utility while the database is active, you may find that some
transactions at least are unrecoverable and at the worst tables may be
corrupted. See the chapter on backups in the manual.
--
Oliver Elphick olly@lfix.co.uk
Isle of Wight http://www.lfix.co.uk/oliver
GPG: 1024D/A54310EA 92C8 39E7 280E 3631 3F0E 1EC0 5664 7A2F A543 10EA
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