Index: head/share/man/man5/periodic.conf.5
===================================================================
--- head/share/man/man5/periodic.conf.5
+++ head/share/man/man5/periodic.conf.5
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 6, 2020
+.Dd November 7, 2020
 .Dt PERIODIC.CONF 5
 .Os
 .Sh NAME
@@ -257,6 +257,20 @@
 Set to
 .Dq Li YES
 to create backup of EFI System Partition (ESP).
+.It Va daily_backup_gmirror_enable
+.Pq Vt bool
+Set to
+.Dq Li YES
+to create backup of gmirror information (i.e., output of
+.Nm gmirror Cm list ) ,
+see
+.Xr gmirror 8 .
+.It Va daily_backup_gmirror_verbose
+.Pq Vt bool
+Set to
+.Dq Li YES
+to report a diff between the new backup and the existing backup
+in the daily output.
 .It Va daily_backup_gpart_enable
 .Pq Vt bool
 Set to
Index: head/usr.sbin/periodic/etc/daily/222.backup-gmirror
===================================================================
--- head/usr.sbin/periodic/etc/daily/222.backup-gmirror
+++ head/usr.sbin/periodic/etc/daily/222.backup-gmirror
@@ -0,0 +1,72 @@
+#!/bin/sh
+
+# $FreeBSD$
+# Created by: Miroslav Lachman <000.fbsd@quip.cz>
+
+# Backup output from `gmirror list`, which provides detailed information
+# of all gmirrors. The backup will be stored in /var/backups/.
+
+# If there is a global system configuration file, suck it in.
+#
+if [ -r /etc/defaults/periodic.conf ]
+then
+	. /etc/defaults/periodic.conf
+	source_periodic_confs
+fi
+
+bak_dir=/var/backups
+
+rotate() {
+	base_name=$1
+	show_diff=$2
+	file="$bak_dir/$base_name"
+
+	if [ -f "${file}.bak" ]; then
+		rc=0
+		if cmp -s "${file}.bak" "${file}.tmp"; then
+			rm "${file}.tmp"
+		else
+			rc=1
+			[ -n "$show_diff" ] && diff "${file}.bak" "${file}.tmp"
+			mv "${file}.bak" "${file}.bak2" || rc=3
+			mv "${file}.tmp" "${file}.bak" || rc=3
+		fi
+	else
+		rc=1
+		mv "${file}.tmp" "${file}.bak" || rc=3
+		[ -n "$show_diff" ] && cat "${file}.bak"
+	fi
+}
+
+case "$daily_backup_gmirror_verbose" in
+	[Yy][Ee][Ss]) show="YES"
+esac
+
+case "$daily_backup_gmirror_enable" in
+	[Yy][Ee][Ss])
+
+	gmirrors=$(gmirror status 2> /dev/null | \
+		awk '$1 ~ /^mirror\// { sub(/mirror\//, ""); print $1 }')
+
+	if [ -z "$gmirrors"  ]; then
+        echo ""
+		echo "daily_backup_gmirror_enable is set to YES but no gmirrors found."
+		rc=2
+	else
+		echo ""
+		echo "Backup of gmirror information for:";
+
+		for m in ${gmirrors}; do
+			echo "$m"
+			safe_name=$(echo "gmirror.${m}" | tr -cs ".[:alnum:]\n" "_")
+			if ! gmirror status -s "${m}" | grep -F -v "COMPLETE"; then
+				gmirror list "${m}" > "$bak_dir/$safe_name.tmp"
+				rotate "$safe_name" $show
+			fi
+		done
+	fi
+	;;
+	*)  rc=0;;
+esac
+
+exit $rc
Index: head/usr.sbin/periodic/etc/daily/Makefile
===================================================================
--- head/usr.sbin/periodic/etc/daily/Makefile
+++ head/usr.sbin/periodic/etc/daily/Makefile
@@ -11,6 +11,7 @@
 	200.backup-passwd \
 	210.backup-aliases \
 	221.backup-gpart \
+	222.backup-gmirror \
 	330.news \
 	400.status-disks \
 	401.status-graid \
Index: head/usr.sbin/periodic/periodic.conf
===================================================================
--- head/usr.sbin/periodic/periodic.conf
+++ head/usr.sbin/periodic/periodic.conf
@@ -79,8 +79,12 @@
 
 # 221.backup-gpart
 daily_backup_gpart_enable="YES"             		# Backup partition table/boot partition/MBR
-daily_backup_gpart_verbose="NO"             		# Be verbose if new backup differs from the new one
+daily_backup_gpart_verbose="NO"             		# Be verbose if new backup differs from the old one
 daily_backup_efi_enable="NO"                		# Backup EFI system partition (ESP)
+
+# 222.backup-gmirror
+daily_backup_gmirror_enable="NO"			# Backup of gmirror info (i.e., output of `gmirror list`)
+daily_backup_gmirror_verbose="NO"			# Log diff if new backup differs from the old one
 
 # 223.backup-zfs
 daily_backup_zfs_enable="NO"				# Backup output from zpool/zfs list