How to backup and restore postgres, How to backup and restore postgres

Question

Hi!
Yesterday I had a major hickup while trying to configure some OD stuff. Since I was still setting up Lion Server, I just decided to go back and restore the system using a Time Machine backup from a few hours earlier. Went well... except that anything to do with postgres was not working anymore: web pages, wiki, iCal, etc Postgres would not start anymore. I could not find anything on the internet and after a few hours of trying gave up and just did a fresh, clean install. Fortunately there were not many user files on yet, but I did lose everything I noted in the wiki since I migrated the old Snow Leopard content.
SO, HERE comes the question: is there a fool-proof way of backing up all Lion Server postgres databases and, more importantly, to actually get the thing back up after a Time Machine restore? I know I can dump all db's using pg_dumpall, but what would be the steps to get this back up and running should I need to? I have restored many MySQL databases in the past, but never were they directly linked to many OS functionalities.
The "Advanced Administration" document of course is not advanced enough for this. Is there anywhere I real guide on "How to restore and make function your Lion Server after a major desaster", like hard disk failure?? Would be very helpful, in case it's needed but also for peace of mind.
Thanks lot! Appreciate any input!
Cheers,
Hendrik

Answer 1

Take my little script here and adjust it to your requirements. I got the base of this script somwhere else and enhanced it myself. Read some explanations below:
# #!/bin/bash
if (test "`whoami`" != "root") then
        echo "You need to be root to start this"
        exit 1
fi
PG_PORT="5432"
PG_USER="_postgres"
PG_BIN="/usr/bin/"
ACT_DATE=$(date '+%y-%m-%d')
EXP_DATE=$(date -v -2w '+%y-%m-%d')
BACKUP_DIR="/Backups/postgres"
LOGFILE=$BACKUP_DIR"/_pg_backup.log"
COMPRESSION="9"
PG_CON="-U $PG_USER"
BACKUP_OPTIONS="$PG_CON -b -C -F c -Z $COMPRESSION"
VACUUM_OPTIONS="$PG_CON -eq"
echo "***** DB_BACKUP $ACT_DATE *****" >>$LOGFILE
for db in `$PG_BIN/psql $PG_CON -lt | sed /\eof/p | grep -v = | awk {'print $1'}`
  do
    # vacuum
    if [ "X" == "X$db" ]; then
          continue;
    fi
    echo $(date '+%c')" -- vacuuming database $db" >> $LOGFILE
    if $PG_BIN/vacuumdb $VACUUM_OPTIONS $db
      then
      #echo "OK!" >>$LOGFILE
          sleep 1
    else
      echo "No Vacuum in database $db!" >>$LOGFILE
    fi
    # backup
    echo $(date '+%c')" -- backing up database $db" >>$LOGFILE
    if  $PG_BIN/pg_dump $BACKUP_OPTIONS -f $BACKUP_DIR/$db-$ACT_DATE.pgdump $db
      then
      if [ -e $BACKUP_DIR/$db-$EXP_DATE.pgdump ]; then
          echo $(date '+%c')" -- deleting old backup" >>$LOGFILE
          rm $BACKUP_DIR/$db-$EXP_DATE.pgdump
      fi
    else
      echo "FAIL Database $db backup!" >>$LOGFILE
    fi
  done
This script dumps all databases in postgres individually.
Databases are vacuumed and then dumped.
Dump-Format is currently set as compressed pgsql dump (See "-F c" in $BACKUP_OPTIONS)
File names consist of "databasename"-"backupdade".pgdump
I have programmed to automatically purge backups older than two weeks (see " -2w " in $EXP_DATE)
If you drop a database you will have to remove backups for that database manually.
I have enabled a daily run of this scrip by placing the executable script somwhere and add it to the crontab of root: sudo crontab -e
Enter the following line and your backups start every day at 6:00. Adjust paths and scriptname according to your own setup.
0 6 * * *       ~/.bin/postgres_dump.sh > /dev/null 2>&1