Re: Moving database install to new SAN

Le jeudi 20 septembre 2007, Joshua D. Drake a écrit :
> Chris Hoover wrote:
> >>> 2. copy whole data directory over to new SAN
> >>
> >> If database is big, then I think that is much faster to copy running
> >> database
> >> to new SAN.
> >> Then stop postgres and rsync what was changed - but this will be
> >> probably only a few files.
> >
> > I believe if you do this, you will not get a function database in the
> > end. There is a lot of data that is held in memory/buffers that may not
> > be flushed to the disks. You have no guarantee you will get this data
> > with this method.
>
> The method would work if they are willing to have an outage. Basically
> you do an initial rsync of the large db...

Perhaps using some tablespace to move the bigest data, then rsync ...

>
> Then you shut down the db.
>
> And rsync again, which will be faster than doing a complete move with
> shutdown.
>
> The key here is, if you use this method... there is *zero* way around
> shutting down the database before the second rsync.
>
>
> Sincerely,
>
> Joshua D. Drake

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