Re: Help with data transfer please

It is my understanding that copying the files that reside in the data
directory are not sufficient for a backup/restore, (because there are file
pointers within the data files I believe, pointers which are no longer valid
on a different server because different blocks get assigned to different
files).  Therefore it follows that an rsync would not be sufficient to keep
the database in sync.

Someone please correct me if my understanding is wrong.

Terry Fielder
Network Engineer
Great Gulf Homes / Ashton Woods Homes
terry@greatgulfhomes.com

> -----Original Message-----
> From: pgsql-general-owner@postgresql.org
> [mailto:pgsql-general-owner@postgresql.org]On Behalf Of
> Andrew Sullivan
> Sent: Monday, June 10, 2002 3:34 PM
> To: pgsql-general
> Subject: Re: [GENERAL] Help with data transfer please
>
>
> On Mon, Jun 10, 2002 at 08:40:36PM +0200, tony wrote:
>
> > > Alternatively, since the database can (presumably) be
> shut down every
> > > night, why not shut down the postmaster at each end and
> use rsync to
> > > synchronise the data directories?  (I haven't tested
> that, and don't
> > > know if it'll work, but I think it should.)
> >
>
> > Set up a cron job that dumps the database.
> > SCP the dump from one machine to the other.
> > Drop the database and recreate it.
> > Import the dump file.
>
> But he said he was trying to reduce long-distance charges as much as
> possible.  Wouldn't rsync (maybe over ssh) keep those charges lower?
> A full dump file on a database of any size can get pretty big, and if
> only one or two data files have changed in the period, you'd only
> need to copy the changes with rsync.  (As I said, I don't know if
> it would work, but it'd be worth testing.)
>
> A
>
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> Andrew Sullivan                               87 Mowat Avenue
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> <andrew@libertyrms.info>                              M6K 3E3
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