mkdir /db_backups

/*
 * Step 1: Write the Script
 * Now that that’s out of the way, we’re going to write a little shell script that creates a
 * directory for the current day, then dumps MongoDB into it. That script looks like this
*/

#!/bin/sh
DIR=`date +%m%d%y`
DEST=/db_backups/$DIR
mkdir $DEST
mongodump -h <your_database_host> -d <your_database_name> -u <username> -p <password> -o $DEST

/*
    Step 2: Set Up cron to Run the Script Nightly
    Now that we have our backup script ready to roll,
    we just need to get it running nightly to perform the backups.
    This is easily done by using cron to run the script.

    On your server, simply open the crontab like this:
*/

sudo crontab -e

45 1 * * * ../../scripts/db_backup.sh

/////////////////////////////////////////////////////////////////////////////
                        OR
                 vi mongobackup.sh

/////////////////////////////////////////////////////////////////////////////
#!/bin/sh

#=====================================================================
# Set the following variables as per your requirement
#=====================================================================
# Database Name to backup
MONGO_DATABASE="mydb"
# Database host name
MONGO_HOST="127.0.0.1"
# Database port
MONGO_PORT="27017"
# Backup directory
BACKUPS_DIR="/var/backups/$MONGO_DATABASE"
# Database user name
DBUSERNAME="username"
# Database password
DBPASSWORD="passw0rd"
# Authentication database name
DBAUTHDB="admin"
# Days to keep the backup
DAYSTORETAINBACKUP="14"
#=====================================================================

TIMESTAMP=`date +%F-%H%M`
BACKUP_NAME="$MONGO_DATABASE-$TIMESTAMP"

echo "Performing backup of $MONGO_DATABASE"
echo "--------------------------------------------"
# Create backup directory
if ! mkdir -p $BACKUPS_DIR; then
  echo "Can't create backup directory in $BACKUPS_DIR. Go and fix it!" 1>&2
  exit 1;
fi;
# Create dump
mongodump -d $MONGO_DATABASE --username $DBUSERNAME --password $DBPASSWORD --authenticationDatabase $DBAUTHDB
# Rename dump directory to backup name
mv dump $BACKUP_NAME
# Compress backup
tar -zcvf $BACKUPS_DIR/$BACKUP_NAME.tgz $BACKUP_NAME
# Delete uncompressed backup
rm -rf $BACKUP_NAME
# Delete backups older than retention period
find $BACKUPS_DIR -type f -mtime +$DAYSTORETAINBACKUP -exec rm {} +
echo "--------------------------------------------"
echo "Database backup complete!"


step 2
chomd +x mongobackup.sh

step3
crontab -e

step4 Enter
00 00 * * * /path/to/script/mongobackup.sh