diff --git a/Manage.c b/Manage.c
index e37f415..bdf2eaf 100644
--- a/Manage.c
+++ b/Manage.c
@@ -452,6 +452,40 @@ static void add_detached(struct mddev_dev *dv, int fd, char disp)
 	}
 }
 
+static void add_set(struct mddev_dev *dv, int fd, char set_char)
+{
+	mdu_array_info_t array;
+	mdu_disk_info_t disk;
+	int remaining_disks;
+	int copies, set;
+	int i;
+
+	if (ioctl(fd, GET_ARRAY_INFO, &array) != 0)
+		return;
+	if (array.level != 10)
+		return;
+	copies = ((array.layout & 0xff) *
+		  ((array.layout >> 8) & 0xff));
+	if (array.raid_disks % copies)
+		return;
+
+	remaining_disks = array.nr_disks;
+	for (i = 0; i < MAX_DISKS && remaining_disks > 0; i++) {
+		char buf[40];
+		disk.number = i;
+		if (ioctl(fd, GET_DISK_INFO, &disk) != 0)
+			continue;
+		if (disk.major == 0 && disk.minor == 0)
+			continue;
+		remaining_disks--;
+		set = disk.raid_disk % copies;
+		if (set_char != set + 'A')
+			continue;
+		sprintf(buf, "%d:%d", disk.major, disk.minor);
+		dv = add_one(dv, buf, dv->disposition);
+	}
+}
+
 int attempt_re_add(int fd, int tfd, struct mddev_dev *dv,
 		   struct supertype *dev_st, struct supertype *tst,
 		   unsigned long rdev,
@@ -1195,6 +1229,35 @@ int Manage_subdevs(char *devname, int fd,
 			continue;
 		}
 
+		if (strncmp(dv->devname, "set-", 4) == 0 &&
+		    strlen(dv->devname) == 5) {
+			int copies;
+
+			if (dv->disposition != 'r' &&
+			    dv->disposition != 'f') {
+				pr_err("'%s' only meaningful with -r or -f\n",
+				       dv->devname);
+				goto abort;
+			}
+			if (array.level != 10) {
+				pr_err("'%s' only meaningful with RAID10 arrays\n",
+				       dv->devname);
+				goto abort;
+			}
+			copies = ((array.layout & 0xff) *
+				  ((array.layout >> 8) & 0xff));
+			if (array.raid_disks % copies != 0 ||
+			    dv->devname[4] < 'A' ||
+			    dv->devname[4] >= 'A' + copies ||
+			    copies > 26) {
+				pr_err("'%s' not meaningful with this array\n",
+				       dv->devname);
+				goto abort;
+			}
+			add_set(dv, fd, dv->devname[4]);
+			continue;
+		}
+
 		if (strchr(dv->devname, '/') == NULL &&
 		    strchr(dv->devname, ':') == NULL &&
 		    strlen(dv->devname) < 50) {
diff --git a/mdadm.8.in b/mdadm.8.in
index 3903470..ef93781 100644
--- a/mdadm.8.in
+++ b/mdadm.8.in
@@ -1273,30 +1273,50 @@ resolved.
 .TP
 .BR \-r ", " \-\-remove
 remove listed devices.  They must not be active.  i.e. they should
-be failed or spare devices.  As well as the name of a device file
+be failed or spare devices.
+
+As well as the name of a device file
 (e.g.
 .BR /dev/sda1 )
 the words
-.B failed
-and
+.BR failed ,
 .B detached
+and names like
+.B set-A
 can be given to
 .BR \-\-remove .
 The first causes all failed device to be removed.  The second causes
 any device which is no longer connected to the system (i.e an 'open'
 returns
 .BR ENXIO )
-to be removed.  This will only succeed for devices that are spares or
-have already been marked as failed.
+to be removed.
+The third will remove a set as describe below under
+.BR \-\-fail .
 
 .TP
 .BR \-f ", " \-\-fail
 Mark listed devices as faulty.
 As well as the name of a device file, the word
 .B detached
-can be given.  This will cause any device that has been detached from
+or a set name like
+.B set\-A
+can be given.  The former will cause any device that has been detached from
 the system to be marked as failed.  It can then be removed.
 
+For RAID10 arrays where the number of copies evenly divides the number
+of devices, the devices can be conceptually divided into sets where
+each set contains a single complete copy of the data on the array.
+Sometimes a RAID10 array will be configured so that these sets are on
+separate controllers.  In this case all the devices in one set can be
+failed by giving a name like
+.B set\-A
+or
+.B set\-B
+to
+.BR \-\-fail .
+The appropriate set names are reported by
+.BR \-\-detail .
+
 .TP
 .BR \-\-set\-faulty
 same as