diff --git a/btrfs-balance.sh b/btrfs-balance.sh
index 978c1fa..967fd8f 100755
--- a/btrfs-balance.sh
+++ b/btrfs-balance.sh
@@ -17,6 +17,12 @@ fi
 LOGIDENTIFIER='btrfs-balance'
 . $(dirname $(realpath "$0"))/btrfsmaintenance-functions
 
+ioprio=
+if [ "$BTRFS_BALANCE_PRIORITY" = "idle" ]; then
+	# ionice(3) idle proirity
+	ioprio="ionice -c 3"
+fi
+
 {
 BTRFS_BALANCE_MOUNTPOINTS=$(expand_auto_mountpoint "$BTRFS_BALANCE_MOUNTPOINTS")
 OIFS="$IFS"
@@ -33,7 +39,7 @@ for MM in $BTRFS_BALANCE_MOUNTPOINTS; do
 	df -H "$MM"
 
 	if detect_mixed_bg "$MM"; then
-		btrfs balance start -musage=0 -dusage=0 "$MM"
+		$ioprio btrfs balance start -musage=0 -dusage=0 "$MM"
 		# we use the MUSAGE values for both, supposedly less aggressive
 		# values, but as the data and metadata space is shared on
 		# mixed-bg this does not lead to the situations we want to
@@ -41,18 +47,18 @@ for MM in $BTRFS_BALANCE_MOUNTPOINTS; do
 		# blockgroups)
 		for BB in $BTRFS_BALANCE_MUSAGE; do
 			# quick round to clean up the unused block groups
-			btrfs balance start -v -musage=$BB -dusage=$BB "$MM"
+			$ioprio btrfs balance start -v -musage=$BB -dusage=$BB "$MM"
 		done
 	else
-		btrfs balance start -dusage=0 "$MM"
+		$ioprio btrfs balance start -dusage=0 "$MM"
 		for BB in $BTRFS_BALANCE_DUSAGE; do
 			# quick round to clean up the unused block groups
-			btrfs balance start -v -dusage=$BB "$MM"
+			$ioprio btrfs balance start -v -dusage=$BB "$MM"
 		done
-		btrfs balance start -musage=0 "$MM"
+		$ioprio btrfs balance start -musage=0 "$MM"
 		for BB in $BTRFS_BALANCE_MUSAGE; do
 			# quick round to clean up the unused block groups
-			btrfs balance start -v -musage="$BB" "$MM"
+			$ioprio btrfs balance start -v -musage="$BB" "$MM"
 		done
 	fi
 
diff --git a/sysconfig.btrfsmaintenance b/sysconfig.btrfsmaintenance
index 4088254..caa50bd 100644
--- a/sysconfig.btrfsmaintenance
+++ b/sysconfig.btrfsmaintenance
@@ -50,6 +50,14 @@ BTRFS_BALANCE_MOUNTPOINTS="/"
 # Frequency of periodic balance.
 BTRFS_BALANCE_PERIOD="weekly"
 
+## Path:        System/File systems/btrfs
+## Type:        string(idle,normal)
+## Default:     "idle"
+#
+# Priority of IO at which the balance process will run. Idle should not degrade
+# performance as much as normal.
+BTRFS_BALANCE_PRIORITY="normal"
+
 ## Path:        System/File systems/btrfs
 ## Type:        string
 ## Default:     "1 5 10 20 30 40 50"