Index: sbin/geom/class/multipath/geom_multipath.c
===================================================================
--- sbin/geom/class/multipath/geom_multipath.c
+++ sbin/geom/class/multipath/geom_multipath.c
@@ -57,27 +57,31 @@
 		{
 			{ 'A', "active_active", NULL, G_TYPE_BOOL },
 			{ 'R', "active_read", NULL, G_TYPE_BOOL },
+			{ 'L', "logicalblock", 0, G_TYPE_NUMBER },
 			G_OPT_SENTINEL
 		},
-		"[-vAR] name prov ..."
+		"[-vAR] [-L logicalblock] name prov ..."
 	},
 	{
 		"label", G_FLAG_VERBOSE | G_FLAG_LOADKLD, mp_main,
 		{
 			{ 'A', "active_active", NULL, G_TYPE_BOOL },
 			{ 'R', "active_read", NULL, G_TYPE_BOOL },
+			{ 'L', "logicalblock", 0, G_TYPE_NUMBER },
 			G_OPT_SENTINEL
 		},
-		"[-vAR] name prov ..."
+		"[-vAR] [-L logicalblock] name prov ..."
 	},
-	{ "configure", G_FLAG_VERBOSE, NULL,
+	{
+		"configure", G_FLAG_VERBOSE, NULL,
 		{
 			{ 'A', "active_active", NULL, G_TYPE_BOOL },
 			{ 'P', "active_passive", NULL, G_TYPE_BOOL },
 			{ 'R', "active_read", NULL, G_TYPE_BOOL },
+			{ 'L', "logicalblock", 0, G_TYPE_NUMBER },
 			G_OPT_SENTINEL
 		},
-		"[-vAPR] name"
+		"[-vAPR] [-L logicalblock] name"
 	},
 	{
 		"add", G_FLAG_VERBOSE, NULL, G_NULL_OPTS,
@@ -148,7 +152,7 @@
 {
 	struct g_multipath_metadata md;
 	off_t disksize = 0, msize;
-	uint8_t *sector, *rsector;
+	uint8_t *sector, *rsector, val;
 	char *ptr;
 	uuid_t uuid;
 	ssize_t secsize = 0, ssize;
@@ -213,10 +217,20 @@
 		return;
 	}
 	strlcpy(md.md_uuid, ptr, sizeof (md.md_uuid));
+	free(ptr);
+
 	md.md_active_active = gctl_get_int(req, "active_active");
 	if (gctl_get_int(req, "active_read"))
 		md.md_active_active = 2;
-	free(ptr);
+	val = gctl_get_int(req, "logicalblock");
+	if (val == 0 || (val > 8 && val < 32))
+		md.md_logicalblock = val;
+	else {
+		gctl_error(req, "Invalid logicalblock bitshift value: %u. "
+			   "Must be a value between 9 and 31, or 0 to disable.",
+			   val);
+		return;
+	}
 
 	/*
 	 * Allocate a sector to write as metadata.
Index: sbin/geom/class/multipath/gmultipath.8
===================================================================
--- sbin/geom/class/multipath/gmultipath.8
+++ sbin/geom/class/multipath/gmultipath.8
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 18, 2015
+.Dd August 8, 2015
 .Dt GMULTIPATH 8
 .Os
 .Sh NAME
@@ -34,16 +34,19 @@
 .Nm
 .Cm create
 .Op Fl ARv
+.Op Fl L Ar logicalblock
 .Ar name
 .Ar prov ...
 .Nm
 .Cm label
 .Op Fl ARv
+.Op Fl L Ar logicalblock
 .Ar name
 .Ar prov ...
 .Nm
 .Cm configure
 .Op Fl APRv
+.Op Fl L Ar logicalblock
 .Ar name
 .Nm
 .Cm add
@@ -134,6 +137,12 @@
 .Fl R
 option enables Active/Read mode, otherwise Active/Passive mode is used
 by default.
+.Pp
+.Fl L
+option enables Logical Block mode, the device is divided into stripes of
+.No 2** Ns Ar logicalblock
+bytes, and all requests to a stripe are served via the same path.
+This can improve performance by taking advantage of read-ahead and caching.
 .It Cm label
 Create multipath device with
 .Dq automatic
@@ -149,6 +158,12 @@
 .Fl R
 option enables Active/Read mode, otherwise Active/Passive mode is used
 by default.
+.Pp
+.Fl L
+option enables Logical Block mode, the device is divided into stripes of
+.No 2** Ns Ar logicalblock
+bytes, and all requests to a stripe are served via the same path.
+This can improve performance by taking advantage of read-ahead and caching.
 .It Cm configure
 Configure the given multipath device.
 .Pp
@@ -158,6 +173,12 @@
 option enables Active/Passive mode,
 .Fl R
 option enables Active/Read mode.
+.Pp
+.Fl L
+option enables Logical Block mode, the device is divided into stripes of
+.No 2** Ns Ar logicalblock
+bytes, and all requests to a stripe are served via the same path.
+This can improve performance by taking advantage of read-ahead and caching.
 .It Cm add
 Add the given provider as a path to the given multipath device.
 Should normally be used only for devices created with
Index: sys/geom/multipath/g_multipath.h
===================================================================
--- sys/geom/multipath/g_multipath.h
+++ sys/geom/multipath/g_multipath.h
@@ -35,9 +35,19 @@
 #define	_G_MULTIPATH_H_
 
 #define	G_MULTIPATH_CLASS_NAME	"MULTIPATH"
-#define	G_MULTIPATH_VERSION	1
 #define	G_MULTIPATH_MAGIC	"GEOM::MULTIPATH"
 
+/*
+ * Version history:
+ * 1 - Initial version number.
+ * 2 - Added Logical Block mode, selects the same path for reads and writes to
+ * nearby sectors, improving cache hit ratios on the controller.
+ */
+#define	G_MULTIPATH_VERSION_01	1
+#define	G_MULTIPATH_VERSION_02	2
+#define	G_MULTIPATH_VERSION	G_MULTIPATH_VERSION_02
+
+
 #include <sys/endian.h>
 
 #ifdef	_KERNEL
@@ -53,6 +63,7 @@
 	int			sc_stopping;
 	int			sc_ndisks;
 	int			sc_active_active; /* Active/Active mode */
+	int			sc_logicalblock; /* logical block mode */
 };
 #endif	/* _KERNEL */
 
@@ -64,16 +75,25 @@
 	uint32_t	md_sectorsize;	/* sectorsize of provider */
 	uint64_t	md_size;	/* absolute size of provider */
 	uint8_t		md_active_active; /* Active/Active mode */
+	uint16_t	md_logicalblock; /* Logical Block mode */
 };
 
 static __inline void
+multipath_metadata_encode_v1(const struct g_multipath_metadata *, u_char *);
+static __inline void
+multipath_metadata_encode_v2(const struct g_multipath_metadata *, u_char *);
+static __inline void
 multipath_metadata_encode(const struct g_multipath_metadata *, u_char *);
 
 static __inline void
+multipath_metadata_decode_v1(u_char *, struct g_multipath_metadata *);
+static __inline void
+multipath_metadata_decode_v2(u_char *, struct g_multipath_metadata *);
+static __inline int
 multipath_metadata_decode(u_char *, struct g_multipath_metadata *);
 
 static __inline void
-multipath_metadata_encode(const struct g_multipath_metadata *md, u_char *data)
+multipath_metadata_encode_v1(const struct g_multipath_metadata *md, u_char *data)
 {
 	bcopy(md->md_magic, data, sizeof(md->md_magic));
 	data += sizeof(md->md_magic);
@@ -91,7 +111,27 @@
 }
 
 static __inline void
-multipath_metadata_decode(u_char *data, struct g_multipath_metadata *md)
+multipath_metadata_encode_v2(const struct g_multipath_metadata *md, u_char *data)
+{
+	bcopy(md->md_magic, data, sizeof(md->md_magic));
+	data += sizeof(md->md_magic);
+	bcopy(md->md_uuid, data, sizeof(md->md_uuid));
+	data += sizeof(md->md_uuid);
+	bcopy(md->md_name, data, sizeof(md->md_name));
+	data += sizeof(md->md_name);
+	le32enc(data, md->md_version);
+	data += sizeof(md->md_version);
+	le32enc(data, md->md_sectorsize);
+	data += sizeof(md->md_sectorsize);
+	le64enc(data, md->md_size);
+	data += sizeof(md->md_size);
+	*data = md->md_active_active;
+	data += sizeof(md->md_active_active);
+	le16enc(data, md->md_logicalblock);
+}
+
+static __inline void
+multipath_metadata_decode_v1(u_char *data, struct g_multipath_metadata *md)
 {
 	bcopy(data, md->md_magic, sizeof(md->md_magic));
 	data += sizeof(md->md_magic);
@@ -107,4 +147,80 @@
 	data += sizeof(md->md_size);
 	md->md_active_active = *data;
 }
+
+static __inline void
+multipath_metadata_decode_v2(u_char *data, struct g_multipath_metadata *md)
+{
+	bcopy(data, md->md_magic, sizeof(md->md_magic));
+	data += sizeof(md->md_magic);
+	bcopy(data, md->md_uuid, sizeof(md->md_uuid));
+	data += sizeof(md->md_uuid);
+	bcopy(data, md->md_name, sizeof(md->md_name));
+	data += sizeof(md->md_name);
+	md->md_version = le32dec(data);
+	data += sizeof(md->md_version);
+	md->md_sectorsize = le32dec(data);
+	data += sizeof(md->md_sectorsize);
+	md->md_size = le64dec(data);
+	data += sizeof(md->md_size);
+	md->md_active_active = *data;
+	data += sizeof(md->md_active_active);
+	md->md_logicalblock = le16dec(data);
+}
+
+static __inline void
+multipath_metadata_encode(const struct g_multipath_metadata *md, u_char *data)
+{
+	u_char *p;
+
+	p = data;
+	p += sizeof(md->md_magic);
+	p += sizeof(md->md_uuid);
+	p += sizeof(md->md_name);
+	le32enc(p, md->md_version);
+	switch (md->md_version) {
+	case G_MULTIPATH_VERSION_01:
+		multipath_metadata_encode_v1(md, data);
+		break;
+	case G_MULTIPATH_VERSION_02:
+		multipath_metadata_encode_v2(md, data);
+		break;
+	default:
+#ifdef _KERNEL
+		panic("%s: Unsupported version %u.", __func__,
+		    (u_int)md->md_version);
+#else
+		assert(!"Unsupported metadata version.");
+#endif
+	}
+}
+
+static __inline int
+multipath_metadata_decode(u_char *data, struct g_multipath_metadata *md)
+{
+	int error;
+	u_char *p;
+
+	error = 0;
+	p = data;
+	bcopy(data, md->md_magic, sizeof(md->md_magic));
+	if (strcmp(md->md_magic, G_MULTIPATH_MAGIC) != 0)
+		return (EINVAL);
+	p += sizeof(md->md_magic);
+	p += sizeof(md->md_uuid);
+	p += sizeof(md->md_name);
+	md->md_version = le32dec(p);
+	switch (md->md_version) {
+	case G_MULTIPATH_VERSION_01:
+		multipath_metadata_decode_v1(data, md);
+		break;
+	case G_MULTIPATH_VERSION_02:
+		multipath_metadata_decode_v2(data, md);
+		break;
+	default:
+		error = EOPNOTSUPP;
+		break;
+	}
+	return (error);
+}
 #endif	/* _G_MULTIPATH_H_ */
Index: sys/geom/multipath/g_multipath.c
===================================================================
--- sys/geom/multipath/g_multipath.c
+++ sys/geom/multipath/g_multipath.c
@@ -170,12 +170,42 @@
 {
 	struct g_multipath_softc *sc;
 	struct g_consumer *best, *cp;
+	int lbselect, cidx;
 
 	sc = gp->softc;
+	/*
+	 * If mode is Active/Passive, use the active component.
+	 * If mode is Active/Read and the request is not a read, use the active
+	 * component.
+	 */
 	if (sc->sc_active_active == 0 ||
 	    (sc->sc_active_active == 2 && bp->bio_cmd != BIO_READ))
 		return (sc->sc_active);
+	/*
+	 * If Mode is Active/Active of Active/Read and Logical Block mode is
+	 * enabled, choose the component based on which Logical Block is being
+	 * requested
+	 */
 	best = NULL;
+	if (sc->sc_logicalblock > 0) {
+		lbselect = (bp->bio_offset >> sc->sc_logicalblock)
+		    % sc->sc_ndisks;
+
+		cidx = 0;
+		LIST_FOREACH(cp, &gp->consumer, consumer) {
+			if (cp->index & MP_BAD) {
+				cidx++;
+				continue;
+			}
+			if (lbselect == cidx)
+				return (cp);
+			cidx++;
+		}
+		/*
+		 * If the consumer we wanted to use is not available,
+		 * fallthrough to the usual algorithm
+		 */
+	}
 	LIST_FOREACH(cp, &gp->consumer, consumer) {
 		if (cp->index & MP_BAD)
 			continue;
@@ -311,6 +341,7 @@
 		md.md_size = size;
 		md.md_sectorsize = ssize;
 		md.md_active_active = sc->sc_active_active;
+		md.md_logicalblock = sc->sc_logicalblock;
 		error = g_multipath_write_metadata(cp, &md);
 		if (error != 0)
 			printf("GEOM_MULTIPATH: Can't update metadata on %s "
@@ -531,6 +562,7 @@
 	memcpy(sc->sc_uuid, md->md_uuid, sizeof (sc->sc_uuid));
 	memcpy(sc->sc_name, md->md_name, sizeof (sc->sc_name));
 	sc->sc_active_active = md->md_active_active;
+	sc->sc_logicalblock = md->md_logicalblock;
 	sc->sc_size = md->md_size;
 	gp->softc = sc;
 	gp->start = g_multipath_start;
@@ -758,9 +790,9 @@
 	g_access(cp, -1, 0, 0);
 	if (buf == NULL)
 		return (error);
-	multipath_metadata_decode(buf, md);
+	error = multipath_metadata_decode(buf, md);
 	g_free(buf);
-	return (0);
+	return (error);
 }
 
 static int
@@ -817,7 +849,7 @@
 			printf("%s is not MULTIPATH\n", pp->name);
 		return (NULL);
 	}
-	if (md.md_version != G_MULTIPATH_VERSION) {
+	if (md.md_version > G_MULTIPATH_VERSION) {
 		printf("%s has version %d multipath id- this module is version "
 		    " %d: rejecting\n", pp->name, md.md_version,
 		    G_MULTIPATH_VERSION);
@@ -1120,6 +1152,17 @@
 	val = gctl_get_paraml(req, "active_read", sizeof(*val));
 	if (val != NULL && *val != 0)
 		md.md_active_active = 2;
+	val = gctl_get_paraml(req, "logicalblock", sizeof(*val));
+	if (val == NULL)
+		md.md_logicalblock = 0;
+	else if (*val == 0 || (*val > 8 && *val < 32))
+		md.md_logicalblock = *val;
+	else {
+		gctl_error(req, "Invalid logicalblock bitshift value: %u. "
+			   "Must be a value between 9 and 31, or 0 to disable.",
+			   *val);
+		return;
+	}
 	gp = g_multipath_create(mp, &md);
 	if (gp == NULL) {
 		gctl_error(req, "GEOM_MULTIPATH: cannot create geom %s/%s\n",
@@ -1171,6 +1214,17 @@
 	val = gctl_get_paraml(req, "active_passive", sizeof(*val));
 	if (val != NULL && *val != 0)
 		sc->sc_active_active = 0;
+	val = gctl_get_paraml(req, "logicalblock", sizeof(*val));
+	if (val == NULL)
+		sc->sc_logicalblock = 0;
+	else if (*val == 0 || (*val > 8 && *val < 32))
+		sc->sc_logicalblock = *val;
+	else {
+		gctl_error(req, "Invalid logicalblock bitshift value: %u. "
+			   "Must be a value between 9 and 31, or 0 to disable.",
+			   *val);
+		return;
+	}
 	if (sc->sc_uuid[0] != 0 && sc->sc_active != NULL) {
 		cp = sc->sc_active;
 		pp = cp->provider;
@@ -1181,6 +1235,7 @@
 		md.md_size = pp->mediasize;
 		md.md_sectorsize = pp->sectorsize;
 		md.md_active_active = sc->sc_active_active;
+		md.md_logicalblock = sc->sc_logicalblock;
 		error = g_multipath_write_metadata(cp, &md);
 		if (error != 0)
 			gctl_error(req, "Can't update metadata on %s (%d)",