Autobackup.sh
Note: The correct title of this article is autobackup.sh. It appears incorrectly here due to technical restrictions.
| Author | Phil Brady |
| Description | Daily database backup at end of day |
| Supports |  
|
Readers may be interested in an approach to automating database backups of a mythtv system.
This mechanism is used with a dedicated mythtv frontend/backend system with Mythwelcome and ACPI Wakeup.
It has been validated with version 0.25 of Mythtv and Mythbuntu 12.04.
AIMS
It was thought that database backups should be taken:
- daily
- on days when recording had been made
- at a time when the system was otherwise idle
- preferably at the end of the day
- if a recording should straddle midnight, the backup should be after that had finished, so 'end of day' needs defining as 4am.
This is achieved by a bash script which calls mythconverg_backup.pl as appropriate. It is called itself from the recording start system event and from within /usr/bin/setwakeup.sh
See Database Backup and Restore for full details of mythconverg_backup.pl.
The script can be placed in /usr/bin/autobackup.sh
autobackup.sh
#!/bin/bash
# Control database backups
# Do a backup after last recording of the day.
# Needs calls planted in start recording event and in setwakeup.sh
# logging if required (remove or write protect the logfile to stop logging)
MYLOGDIR=/var/log/mythtv
MYLOGF=autobackup.log
MYLOG=$MYLOGDIR/$MYLOGF
if [ -w $MYLOG ]; then
if [ $(find $MYLOGDIR -name $MYLOGF -size +20M) ]; then
#tidy log
if [ -w $MYLOG.1 ]; then cp $MYLOG $MYLOG.1 ; fi
cp /dev/null $MYLOG
fi
else
MYLOG=/dev/null
fi
echo "$(date +%F" "%T) $(whoami) called $0 $1 $2" >> $MYLOG
#database backup directory
[ -r $HOME/.mythtv/backuprc ] &&\
source $HOME/.mythtv/backuprc
BACKUPDIR=${DBBackupDirectory:-/var/lib/mythtv/db_backups}
#file to indicate recording has been made
MYRECFILE="${BACKUPDIR}/RecordingDone"
#file showing time of last backup
MYLASTBACKUP="${BACKUPDIR}/BackupDone"
#recordings backup directory
#MYRECDIR=/var/lib/mythtv2/recordings
if [ $# -eq 0 ]; then
echo " need parameter">>$MYLOG
echo "Needs parameter: try $0 --help"
exit
elif [ $1 == "--recording" ]; then
#start of recording
if [ -e $MYRECFILE ]; then
echo " previous recording noted">>$MYLOG
else
touch $MYRECFILE
chmod 666 $MYRECFILE
echo " $MYRECFILE created">>$MYLOG
fi
elif [ $1 == "--setwake" ]; then
#System about to close down - see if backup needed first
echo " this wakeup time is $(date +%F" "%T --date=@${2})">>$MYLOG
if [ ! -e $MYRECFILE ]; then
echo " no recordings to backup">>$MYLOG
exit
fi
TODAY=$(($(date +%s) - 14400)) #offset by 4 hours
TODAY=$((TODAY/86400))
BACKUPDAY=0
if [ -e $MYLASTBACKUP ]; then
BACKUPDAY=$(($(date --reference=${MYLASTBACKUP} +%s)- 14400))
BACKUPDAY=$((BACKUPDAY/86400))
fi
if [ $BACKUPDAY -eq $TODAY ]; then
echo " backup already done today">>$MYLOG
exit
fi
WAKEDAY=$((${2}-14400))
WAKEDAY=$((WAKEDAY/86400))
if [ $WAKEDAY -eq $TODAY ]; then
echo " Another recording expected today">>$MYLOG
exit
fi
RECDAY=$(($(date --reference=${MYRECFILE} +%s)- 14400))
RECDAY=$((RECDAY/86400))
if [ $((WAKEDAY-RECDAY)) -ge 1 ];then # 1 is interval in days - change if necessary
#update marker file then do a db backup
touch ${MYLASTBACKUP}
/usr/share/mythtv/mythconverg_backup.pl --directory ${BACKUPDIR} --rotate 10 >>$MYLOG 2>&1
#did it work?
if [ $(find $BACKUPDIR -name 'mythconverg*.sql.gz' -size +5000k -newer $MYLASTBACKUP | wc -l) -gt 0 ]; then
echo " db backup finished at $(date +%F" "%T)" >> $MYLOG
else
echo " DATABASE BACKUP FAILED at $(date +%F" "%T)" >> $MYLOG
fi
rm $MYRECFILE
if [ -x /usr/bin/autobackup.pl ]; then
echo " Starting backup of recordings">>$MYLOG
/usr/bin/autobackup.pl >> $MYLOG 2>&1
echo " Recordings backup finished at $(date +%F" "%T)" >> $MYLOG
fi
else
echo " Backup not due yet">>$MYLOG
fi
else
#assume help needed
echo ""
echo "Do backups of database at end of day provided a recording has taken place"
echo ""
echo " 1. Make this script available and executable in /usr/bin"
echo " 2. Create backup directory and permissions and set BACKUPDIR in"
echo " this script. Default is ${BACKUPDIR}"
echo " 3. Create log file with chmod 666 and set MYLOG."
echo " default is /var/log/mythtv/autobackup.log"
echo " no logging will take place if this file is not writable"
echo " 4. Ditto /var/log/mythtv/autobackup.log.1"
echo " 5. Copy the link ~/.mythtv/config.xml to /home/mythtv/.mythtv/config.xml"
echo " 6. Plant /usr/bin/autobackup.sh --recording in recording start event"
echo " 7. plant /usr/bin/autobackup.sh --setwake \$1 in /usr/bin/setwakeup.sh"
echo ' ($1 is wakeuptime in secs since 1970)'
echo ""
echo "To also backup 'best' recordings:"
echo " 8. Create backup partition and directory,"
echo " 9. place autobackup.pl in /usr/bin and make it executable."
echo "10. check parameters, here and in perl script."
echo " see autobackup.pl --help"
echo ""
echo ""
echo "Calling parameters to this script are:"
echo " --setwake <wakeuptime>"
echo " --recording"
exit
fi
#database restore reminder: eg
# /usr/share/mythtv/mythconverg_restore.pl\
# --drop_database --create_database\
# --directory /var/lib/mythtv/db_backups\
# --filename mythconverg-1214-20080626150513.sql.gz
Execute permissions need to be set; two log files need creating and a directory creating for the backups:
#make script executable sudo chmod 755 /usr/bin/autobackup.sh #create log files sudo touch /var/log/mythtv/autobackup.log sudo touch /var/log/mythtv/autobackup.log.1 sudo chmod 666 /var/log/mythtv/autobackup.* #create backup directory sudo mkdir /var/lib/mythtv/db_backups sudo chmod 777 /var/lib/mythtv/db_backups
The user mythtv will be performing the backups. If the file (or link) /home/mythtv/.mythtv/config.xml does not exist then it will need creating so the backup system can access the database. However, if the file or link already exists then omit this step.
sudo cp ~/.mythtv/config.xml /home/mythtv/.mythtv/config.xml
The system needs to be triggered by the ‘Recording Start’ system event (frontend, setup, system events) which needs to be set to
/usr/bin/autobackup.sh --recording
It is also triggered in the /usr/bin/setwakeup.sh script which passes next wakeup time to the script and allows it to detect whether it is the last closedown of the 4am to 4am day and perform the database backup.
The standard setwakeup script is modified as follows:
#!/bin/sh #$1 is the first argument to the script. It is the time in seconds since 1970 #this is defined in mythtv-setup with the time_t argument echo 0 > /sys/class/rtc/rtc0/wakealarm #this clears your alarm. echo $1 > /sys/class/rtc/rtc0/wakealarm #this writes your alarm #do database backup if appropriate if [ -x /usr/bin/autobackup.sh ]; then /usr/bin/autobackup.sh --setwake $1 fi
Logging
The script placed logging information in /var/log/mythtv/autobackup.log and rotates it as necessary to /var/log/mythtv/autobackup.log.1 If logging is not required, simply remove these log files.
Backing up Recordings
If the file /usr/bin/autobackup.pl is present, then the script will also trigger a selective backup of recordings. The 'best set' which fits within the available space will be chosen and transferred. See autobackup.pl for details.
