- if [ -d "$MYSQL_BACKUP_DIR" ]; then
- echo_error "Error: $MYSQL_BACKUP_DIR exists already. Likely an upgrade failed previously"
- exit 1
- fi
- mkdir "$MYSQL_BACKUP_DIR"
- if [ $? -ne 0 ]; then
- echo_error "Error: could not create temporary backup directory $MYSQL_BACKUP_DIR"
- exit 1
- fi
-
- # the /root/.my.cnf is needed because we set the mysql root
- # password from liberty onwards
- backup_flags="--defaults-extra-file=/root/.my.cnf -u root --flush-privileges --all-databases --single-transaction"
- # While not ideal, this step allows us to calculate exactly how much space the dump
- # will need. Our main goal here is avoiding any chance of corruption due to disk space
- # exhaustion
- backup_size=$(mysqldump $backup_flags 2>/dev/null | wc -c)
- database_size=$(du -cb /var/lib/mysql | tail -1 | awk '{ print $1 }')
- free_space=$(df -B1 --output=avail "$MYSQL_BACKUP_DIR" | tail -1)
-
- # we need at least space for a new mysql database + dump of the existing one,
- # times a small factor for additional safety room
- # note: bash doesn't do floating point math or floats in if statements,
- # so use python to apply the ratio and cast it back to integer
- required_space=$(python -c "from __future__ import print_function; print(\"%d\" % int((($database_size + $backup_size) * $MYSQL_BACKUP_SIZE_RATIO)))")
- if [ $required_space -ge $free_space ]; then
- echo_error "Error: not enough free space in $MYSQL_BACKUP_DIR ($required_space bytes required)"
- exit 1
- fi
-