Thursday, June 19, 2008

Re: [PERFORM] WAL DUDAS

Antonio Perez wrote:
[wonders why his online backup / recovery test didn't work]

> 1. Se crea una instancia de postgreSQL
>
> 2. Se crea un directorio $PGDATA/walback donde se almacenararn los wal antiguos
>
> 3. Se exporta una variable $PGDATA2 que es la ubicacion del respaldo del contenido de $PGDATA
>
> 4. Se activa el wal
>
> 5. Se crea una BD y una tabla
>
> 6. En psql se ejecuta pg_start_backup('etiqueta');
>
> 7. Se realiza una copia de todo lo que esta en $PGDATA hacia otro directorio ($PGDATA2)
>
> 8. En psql se ejecuta pg_stop_backup();
>
> 9. Se actualiza el valor de un registro en la tabla que se creo
>
> 10. Se baja la instancia
>
> 11. Se copia todo el contenido de $PGDATA/pg_xlog y $PGDATA/walback en $PGDATA2/pg_xlog y $PGDATA2/walback
>
> 12. Se inicia la instancia con pg_ctl -D $PGDATA2 --log $PGDATA2/log.log start
>
> 13. Se ejecuta psql
>
> 14. Se consulta la tabla y no existen registro
>
> Si alguien sabe el porque pasa esto me avisan. Gracias

First, you are supposed to use English on this list.

What you did with your copy of the cluster files is a crash recovery, basically
the same thing that will take place if you kill -9 the postmaster and restart it.

This is not the correct way to restore, left alone to recover the database.

There are step-by-step instructions at

http://www.postgresql.org/docs/current/static/continuous-archiving.html#BACKUP-PITR-RECOVERY


The important step you missed is step number 7 in which you create a recovery.conf
file that tells the server where it should look for archived WAL files, how to restore
them and until what point in time it should recover.

Yours,
Laurenz Albe

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