diff --git a/backup-mysql.sh b/backup-mysql.sh
index e948a41..4be4797 100755
--- a/backup-mysql.sh
+++ b/backup-mysql.sh
@@ -7,15 +7,29 @@
 #  $ mysqldump -AcfFl --flush-privileges | pbzip2 -c > backup.sql.bz2
 #
 # However, most of the databases do not change much or do not change at all
-# over the day, yet the resulting .bz2 had to be generated every day. The
-# compressed result _did_ change however and to be transferred in full over a
-# 128 kbps line to our backup host. This one is slightly more complicated,
-# but should suffice.
+# over the day, yet the resulting compressed dump had to be generated every
+# day, *did* change and had to be transferred in full over a 128 kbps line
+# to our backup host. This one is slightly more complicated, but should do
+# the trick.
 #
-# Privileges needed: SELECT, RELOAD, LOCK TABLES
+# Notes:
+# - If INFORMATION_SCHEMA.TABLES would work for InnoDB tables, we could query if the
+#   database has changed, and only backup if needed.
+#   * https://bugs.mysql.com/bug.php?id=2681
+#     Ability to determine when DB was last modified (generic method)
 #
-PATH=/bin:/usr/bin:/usr/local/bin:/opt/csw/bin:/usr/sfw/bin
-HASH=sha1			# See 'openssl dgst -h' for possible values
+# - We had to drop the sys.metrics view. The whole sys schema may not be needed at all.
+# * https://mariadb.com/kb/en/sys-schema/
+# * https://mariadb.com/kb/en/sys-schema/
+# * https://forums.cpanel.net/threads/remove-sys-database-after-upgrade-to-from-mysql-5-7-to-mariadb-10-3.674045/
+#   > "MariaDB does not utilize the sys schema. If you upgrade from MySQL 5.7 to MariaDB, you must
+#   > manually remove the sys database, because it can cause unnecessary errors during certain check table calls."
+#
+#
+    PATH=/bin:/usr/bin:/usr/local/bin
+   RUNAS=mysql				# Privileges needed: SELECT, RELOAD, LOCK TABLES
+COMPRESS=zstd
+ LOGFILE=backup-mysql.log
 
 # unset me!
 # DEBUG=echo
@@ -25,103 +39,101 @@ if [ ! -d "$1" ]; then
 	exit 1
 else
 	DIR="$1"
+	cd "$DIR" || exit 3
 fi
 
-# Use 'gdate' if available, 'date' otherwise
-if [ "$(which gdate)" ]; then
-	DATE="gdate"
-else
-	DATE="date"
+# Don't run as root, but we need to own $DIR
+if [ ! "$(whoami)" = "${RUNAS}" ]; then
+	echo "Please execute as user \"${RUNAS}\"!"
+	exit 2
 fi
 
-$DATE
+# Be nice to others
+renice 20 $$ > /dev/null
+
+# The date should end up in a logfile
+date >> "${LOGFILE}"
+
 # We have checks too :-)
 if [ "$2" = "-c" ]; then
-	for f in "${DIR}"/*.bz2; do
-		printf '..%s..' "Processing ${f} ($(stat -c 'scale=0; %s / 1024' "${f}" | bc -l)KB)..."
-		grep -q "$(bzip2 -dc "$f" | openssl ${HASH}) $(echo "${f}" | sed "s/.bz2$/.${HASH}/")"
-		if [ $? = 0 ]; then
+	for f in *.zst; do
+		printf "%s" "Processing \"$f\" ($(stat -c 'scale=0; %s / 1024' "$f" | bc -l) KB)..."
+		if grep -q "$(${COMPRESS} -qdc "$f" | sha1sum | awk '{print $1}')" "${f%%.zst}".sha1; then
 			echo "checksum OK"
 		else
 			echo "checksum FAILED"
 		fi
 	done
-exit 0
+exit $?
 fi
 
-BEGIN=$($DATE +%s)
-for db in $(mysql --batch --skip-column-names -e 'show databases' | sort); do
-	printf '..%s..' "Backing up ${db}...."
-	# - Use multiple-row INSERT syntax that include several VALUES lists
-	# - Continue even if an SQL error occurs during a table dump
-	# - Flush the MySQL server log files before starting the dump
-	# - Send a FLUSH PRIVILEGES statement to the server after dumping the mysql database
-	# - Lock all tables to be dumped before dumping them
-	# - Dump binary columns using hexadecimal notation
-	# - Using --skip-dump-date (added in v5.0.52) so that the dump won't change unnecessarily.
-	# - Included stored routines
-	# - Include triggers for each dumped table
+# DB credentials
+OPTIONS="--user=backup --password=XXXX"				# Can't we just use ~/.my.cnf?
+
+# Main loop
+BEGIN=$(date +%s)
+for db in $(mysql ${OPTIONS} --batch --skip-column-names -e 'show databases' | sort); do
 	case "${db}" in
-	performance_schema|information_schema)
+	information_schema|performance_schema)
 		# Access denied for user 'root'@'localhost' to database 'information_schema' when using LOCK TABLES
-		# > mysqldump incorrectly tries to LOCK TABLES on the information_schema database.
-		# > https://bugs.mysql.com/bug.php?id=21527 (closed)
-		#
-		# > mysqldump can not dump INFORMATION_SCHEMA
-		# > https://bugs.mysql.com/bug.php?id=33762 (closed)
-		#
-		# > mysqldump: problems dumping INFORMATION_SCHEMA
-		# > https://bugs.mysql.com/bug.php?id=49633 (verified)
-		OPTIONS="--extended-insert --force --flush-logs --flush-privileges --skip-lock-tables --hex-blob --routines --triggers"
+		# http://bugs.mysql.com/bug.php?id=21527 (closed)
+		# http://bugs.mysql.com/bug.php?id=33762 (closed)
+		# http://bugs.mysql.com/bug.php?id=49633
+		# OPTIONS="${OPTIONS} --skip-lock-tables"
+		continue
 	;;
 
-	*)
-		OPTIONS="--extended-insert --force --flush-logs --flush-privileges --lock-tables      --hex-blob --routines --triggers"
-	;;
+	# mysql)
+	#	# - Skip mysql.event, http://bugs.mysql.com/bug.php?id=68376
+	#	# - We used to add --skip-events b/c of http://bugs.debian.org/673572 - but this triggers #68376 again!
+	#	OPTIONS="${OPTIONS} --ignore-table=mysql.event"
+	# ;;
 	esac
 
-	if [ -n "${DEBUG}" ]; then
-		${DEBUG} mysqldump "${OPTIONS}" "${db}"   grep -Ev -- '^-- Dump completed on'   "${DIR}/DB_${db}.sql.new"
-	else
-		${DEBUG} mysqldump "${OPTIONS}" "${db}" | grep -Ev -- '^-- Dump completed on' > "${DIR}/DB_${db}.sql.new"
-	fi
+	# Backup!
+	$DEBUG mysqldump ${OPTIONS} --lock-tables --skip-dump-date --result-file="DB_${db}.sql.new" --databases "${db}"
 	
-	# We're comparing checksum rather than the whole dump, so that we
-	# can compress them afterwards and still be able to compare tomorrow's dump.
+	# We're comparing checksums rather than the whole dump, so that we can compress
+	# them afterwards and still be able to compare tomorrow's dump.
 	# - If  a checksum file is present, create a new one and compare them
 	# - If no checksum file is present, create one
-	if [ -f "${DIR}/DB_${db}.sql.${HASH}" ]; then
-		if [ -n "${DEBUG}" ]; then
-			${DEBUG} openssl ${HASH} "${DIR}/DB_${db}.sql.new"   sed 's/\.new$//'   "${DIR}/DB_${db}.sql.new.${HASH}"
-		else
-			${DEBUG} openssl ${HASH} "${DIR}/DB_${db}.sql.new" | sed 's/\.new$//' > "${DIR}/DB_${db}.sql.new.${HASH}"
-		fi
-		H_OLD=$(awk '{print $NF}' "${DIR}/DB_${db}.sql.${HASH}"     2>/dev/null)
-		H_NEW=$(awk '{print $NF}' "${DIR}/DB_${db}.sql.new.${HASH}" 2>/dev/null)
+	if [ -f DB_"${db}".sql.sha1 ]; then
+		$DEBUG sha1sum DB_"${db}".sql.new > DB_"${db}".sql.new.sha1
+		sed 's/\.new$//' -i DB_"${db}".sql.new.sha1
+
+		H_OLD=$(awk '{print $1}' DB_"${db}".sql.sha1     2>/dev/null)
+		H_NEW=$(awk '{print $1}' DB_"${db}".sql.new.sha1 2>/dev/null)
 		
-		# - If they are equal, delete our new one, otherwise update the old one
+		# If they are equal, delete our new one, otherwise update the old one
 		if [ "$H_OLD" = "$H_NEW" ]; then
-			echo "database ${db} has not changed, nothing to do."
-			${DEBUG} rm "${DIR}/DB_${db}.sql.new" "${DIR}/DB_${db}.sql.new.${HASH}"
+			echo "Database ${db} has not changed, nothing to do" >> "${LOGFILE}"
+			$DEBUG rm DB_"${db}".sql.new DB_"${db}".sql.new.sha1
 		else
-			echo "database ${db} changed!"
-			${DEBUG} mv "${DIR}/DB_${db}.sql.new.${HASH}" "${DIR}/DB_${db}.sql.${HASH}"
-			${DEBUG} mv "${DIR}/DB_${db}.sql.new"         "${DIR}/DB_${db}.sql"
-			${DEBUG} pbzip2 -f "${DIR}/DB_${db}.sql"
+			echo "Database ${db} has changed, discarding the old dump." >> "${LOGFILE}"
+			$DEBUG mv -f DB_"${db}".sql.new.sha1 DB_"${db}".sql.sha1
+			$DEBUG mv -f DB_"${db}".sql.new      DB_"${db}".sql
+			$DEBUG ${COMPRESS} --rm -9qf DB_"${db}".sql
 		fi
 	else
-		# - We have nothing to compare
-		echo "database ${db} must be new?"
-		${DEBUG} mv "${DIR}/DB_${db}.sql.new" "${DIR}/DB_${db}.sql"
-		if [ -n "${DEBUG}" ]; then
-			${DEBUG} openssl ${HASH} "${DIR}/DB_${db}.sql"   "${DIR}/DB_${db}.sql.${HASH}"
-		else
-			${DEBUG} openssl ${HASH} "${DIR}/DB_${db}.sql" > "${DIR}/DB_${db}.sql.${HASH}"
-		fi
-		${DEBUG} pbzip2 -f "${DIR}/DB_${db}.sql"
+		# We have nothing to compare
+		echo "No checksum found for database ${db}." >> "${LOGFILE}"
+		$DEBUG mv -f DB_"${db}".sql.new DB_"${db}".sql
+		$DEBUG sha1sum DB_"${db}".sql > DB_"${db}".sql.sha1
+		$DEBUG ${COMPRESS} --rm -9qf DB_"${db}".sql
 	fi
-	${DEBUG}
 done
-END=$(${DATE} +%s)
-echo "$0 finished after $(echo "${END}" - "${BEGIN}" | bc) seconds."
-echo
+END=$(date +%s)
+echo "${0} finished after $(echo \( "${END}" - "${BEGIN}" \) / 60 | bc) minutes." >> "${LOGFILE}"
+echo >> "${LOGFILE}"
+
+### OLD ###
+#	printf "%s" "Backing up \"${db}\"...." >> "${LOGFILE}"
+	# - Use multiple-row INSERT syntax that include several VALUES lists
+	# - Continue even if an SQL error occurs during a table dump
+	# - Flush the MySQL server log files before starting the dump
+	# - Send a FLUSH PRIVILEGES statement to the server after dumping the mysql database
+	# - Dump binary columns using hexadecimal notation
+	# - Using --skip-dump-date (added in v5.0.52) so that the dump won't change unnecessarily.
+	# - Included stored routines
+	# - Include triggers for each dumped table
+#	OPTIONS="${OPTIONS} --extended-insert --force --flush-logs --flush-privileges --hex-blob --skip-dump-date --routines --triggers"