What's the best way to automate backing-up of PostgreSQL databases?

Solution 1:

the same as you do for any other repetitive task that can be automated - you write a script to do the backup, and then set up a cron job to run it.

a script like the following, for instance:

(Note: it has to be run as the postgres user, or any other user with the same privs)

#! /bin/bash

# backup-postgresql.sh
# by Craig Sanders <[email protected]>
# This script is public domain.  feel free to use or modify
# as you like.

DUMPALL='/usr/bin/pg_dumpall'
PGDUMP='/usr/bin/pg_dump'
PSQL='/usr/bin/psql'

# directory to save backups in, must be rwx by postgres user
BASE_DIR='/var/backups/postgres'
YMD=$(date "+%Y-%m-%d")
DIR="$BASE_DIR/$YMD"
mkdir -p "$DIR"
cd "$DIR"

# get list of databases in system , exclude the tempate dbs
DBS=( $($PSQL --list --tuples-only |
          awk '!/template[01]/ && $1 != "|" {print $1}') )

# first dump entire postgres database, including pg_shadow etc.
$DUMPALL --column-inserts | gzip -9 > "$DIR/db.out.gz"

# next dump globals (roles and tablespaces) only
$DUMPALL --globals-only | gzip -9 > "$DIR/globals.gz"

# now loop through each individual database and backup the
# schema and data separately
for database in "${DBS[@]}" ; do
    SCHEMA="$DIR/$database.schema.gz"
    DATA="$DIR/$database.data.gz"
    INSERTS="$DIR/$database.inserts.gz"

    # export data from postgres databases to plain text:

    # dump schema
    $PGDUMP --create --clean --schema-only "$database" |
        gzip -9 > "$SCHEMA"

    # dump data
    $PGDUMP --disable-triggers --data-only "$database" |
        gzip -9 > "$DATA"

    # dump data as column inserts for a last resort backup
    $PGDUMP --disable-triggers --data-only --column-inserts \
        "$database" | gzip -9 > "$INSERTS"

done

# delete backup files older than 30 days
echo deleting old backup files:
find "$BASE_DIR/" -mindepth 1 -type d -mtime +30 -print0 |
    xargs -0r rm -rfv

EDIT :
pg_dumpall -D switch (line 27) is deprecated, now replaced with --column-inserts
https://wiki.postgresql.org/wiki/Deprecated_Features

Solution 2:

pg_dump dbname | gzip > filename.gz

Reload with

createdb dbname
gunzip -c filename.gz | psql dbname

or

cat filename.gz | gunzip | psql dbname

Use split. The split command allows you to split the output into pieces that are acceptable in size to the underlying file system. For example, to make chunks of 1 megabyte:

pg_dump dbname | split -b 1m - filename

Reload with

createdb dbname
cat filename* | psql dbname

Your could toss one of those in /etc/cron.hourly

Sourced from http://www.postgresql.org/docs/8.1/interactive/backup.html#BACKUP-DUMP-ALL

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Solution 3:

Whatever commands you issue "by hand", - write them to script, and put call to this script in cron or whatever scheduler you use.

You can of course make the script more fancy, but generally, I think that you'll get there - start simple, and later refine.

Simplest possible script:

#!/bin/bash
/usr/local/pgsql/bin/pg_dumpall -U postgres -f /var/backups/backup.dump

Save it as /home/randell/bin/backup.sh, add to cron:

0 0 * * 0 /home/randell/bin/backup.sh