diff --git a/libcheckers/checkers.c b/libcheckers/checkers.c
index 53770a6..1c08864 100644
--- a/libcheckers/checkers.c
+++ b/libcheckers/checkers.c
@@ -17,6 +17,7 @@ static struct checker checkers[] = {
 		.context    = NULL,
 		.check      = directio,
 		.init       = directio_init,
+	        .size_scxt  = directio_size_scxt,
 		.free       = directio_free
 	},
 	{
@@ -26,6 +27,7 @@ static struct checker checkers[] = {
 		.context    = NULL,
 		.check      = tur,
 		.init       = tur_init,
+		.size_scxt  = tur_size_scxt,
 		.free       = tur_free
 	},
 	{
@@ -35,6 +37,7 @@ static struct checker checkers[] = {
 		.context    = NULL,
 		.check      = hp_sw,
 		.init       = hp_sw_init,
+		.size_scxt  = hp_sw_size_scxt,
 		.free       = hp_sw_free
 	},
 	{
@@ -44,6 +47,7 @@ static struct checker checkers[] = {
 		.context    = NULL,
 		.check      = emc_clariion,
 		.init       = emc_clariion_init,
+		.size_scxt  = emc_clariion_size_scxt,
 		.free       = emc_clariion_free
 	},
 	{
@@ -53,9 +57,10 @@ static struct checker checkers[] = {
 		.context    = NULL,
 		.check      = readsector0,
 		.init       = readsector0_init,
+		.size_scxt  = readsector0_size_scxt,
 		.free       = readsector0_free
 	},
-	{0, "", "", NULL, NULL, NULL, NULL},
+	{0, "", "", NULL, NULL, NULL, NULL, NULL},
 };
 
 void checker_set_fd (struct checker * c, int fd)
@@ -75,8 +80,14 @@ struct checker * checker_lookup (char * 
 	return NULL;
 }
 
-int checker_init (struct checker * c)
+unsigned long checker_size_scxt (struct checker * c)
 {
+	return c->size_scxt();
+}
+
+int checker_init (struct checker * c, void * mpctxt)
+{
+	c->mpcontext = mpctxt;
 	return c->init(c);
 }
 
@@ -127,5 +138,6 @@ void checker_get (struct checker * dst, 
 	strncpy(dst->message, src->message, CHECKER_MSG_LEN);
 	dst->check = src->check;
 	dst->init = src->init;
+	dst->size_scxt = src->size_scxt;
 	dst->free = src->free;
 }
diff --git a/libcheckers/checkers.h b/libcheckers/checkers.h
index 219dfaf..b0282eb 100644
--- a/libcheckers/checkers.h
+++ b/libcheckers/checkers.h
@@ -83,14 +83,18 @@ struct checker {
 	char name[CHECKER_NAME_LEN];
 	char message[CHECKER_MSG_LEN];       /* comm with callers */
 	void * context;                      /* store for persistent data */
+	void * mpcontext;                    /* store for persistent data */
+                                             /* shared multipath-wide */
 	int (*check)(struct checker *);
 	int (*init)(struct checker *);       /* to allocate the context */
+	unsigned long (*size_scxt)(void);    /* get size for shared context */
 	void (*free)(struct checker *);      /* to free the context */
 };
 
 #define MSG(c, a) snprintf((c)->message, CHECKER_MSG_LEN, a);
 
-int checker_init (struct checker *);
+int checker_init (struct checker *, void *);
+unsigned long checker_size_scxt (struct checker *);
 void checker_put (struct checker *);
 void checker_reset (struct checker * c);
 void checker_set_fd (struct checker *, int);
diff --git a/libcheckers/directio.c b/libcheckers/directio.c
index b53c1c3..819af37 100644
--- a/libcheckers/directio.c
+++ b/libcheckers/directio.c
@@ -59,6 +59,11 @@ out:
 	return 1;
 }
 
+unsigned long directio_size_scxt (void)
+{
+	return 0;
+}
+
 void directio_free (struct checker * c)
 {
 	struct directio_context * ct = (struct directio_context *)c->context;
diff --git a/libcheckers/directio.h b/libcheckers/directio.h
index 1865b1f..5e9e6df 100644
--- a/libcheckers/directio.h
+++ b/libcheckers/directio.h
@@ -3,6 +3,7 @@
 
 int directio (struct checker *);
 int directio_init (struct checker *);
+unsigned long directio_size_scxt (void);
 void directio_free (struct checker *);
 
 #endif /* _DIRECTIO_H */
diff --git a/libcheckers/emc_clariion.c b/libcheckers/emc_clariion.c
index a883e3d..f60026b 100644
--- a/libcheckers/emc_clariion.c
+++ b/libcheckers/emc_clariion.c
@@ -33,6 +33,11 @@ int emc_clariion_init (struct checker * 
 	return 0;
 }
 
+unsigned long emc_clariion_size_scxt (void)
+{
+	return 0;
+}
+
 void emc_clariion_free (struct checker * c)
 {
 	free(c->context);
diff --git a/libcheckers/emc_clariion.h b/libcheckers/emc_clariion.h
index a1018a6..0cac45d 100644
--- a/libcheckers/emc_clariion.h
+++ b/libcheckers/emc_clariion.h
@@ -3,6 +3,7 @@
 
 int emc_clariion (struct checker *);
 int emc_clariion_init (struct checker *);
+unsigned long emc_clariion_size_scxt (void);
 void emc_clariion_free (struct checker *);
 
 #endif /* _EMC_CLARIION_H */
diff --git a/libcheckers/hp_sw.c b/libcheckers/hp_sw.c
index b9731ff..58e0011 100644
--- a/libcheckers/hp_sw.c
+++ b/libcheckers/hp_sw.c
@@ -39,6 +39,11 @@ int hp_sw_init (struct checker * c)
 	return 0;
 }
 
+unsigned long hp_sw_size_scxt (void)
+{
+	return 0;
+}
+
 void hp_sw_free (struct checker * c)
 {
 	return;
diff --git a/libcheckers/hp_sw.h b/libcheckers/hp_sw.h
index 3be0d8e..46dad47 100644
--- a/libcheckers/hp_sw.h
+++ b/libcheckers/hp_sw.h
@@ -3,6 +3,7 @@
 
 int hp_sw (struct checker *);
 int hp_sw_init (struct checker *);
+unsigned long hp_sw_size_scxt (void);
 void hp_sw_free (struct checker *);
 
 #endif /* _HP_SW_H */
diff --git a/libcheckers/readsector0.c b/libcheckers/readsector0.c
index dd18528..f76c34e 100644
--- a/libcheckers/readsector0.c
+++ b/libcheckers/readsector0.c
@@ -14,6 +14,7 @@
 #include "checkers.h"
 
 #include "../libmultipath/sg_include.h"
+#include "../libmultipath/debug.h"
 
 #define SENSE_BUFF_LEN 32
 
@@ -29,12 +30,18 @@ int readsector0_init (struct checker * c
 	return 0;
 }
 
+unsigned long readsector0_size_scxt (void)
+{
+	return 0;
+}
+
 void readsector0_free (struct checker * c)
 {
 	return;
 }
 
 int
+//sg_read (int sg_fd, unsigned char * buff)
 sg_read (int sg_fd, unsigned char * buff, unsigned char * senseBuff)
 {
 	/* defaults */
@@ -45,10 +52,12 @@ sg_read (int sg_fd, unsigned char * buff
 	int * diop = NULL;
 
 	unsigned char rdCmd[cdbsz];
+	unsigned char *sbb = senseBuff;
 	struct sg_io_hdr io_hdr;
 	int res;
 	int rd_opcode[] = {0x8, 0x28, 0xa8, 0x88};
 	int sz_ind;
+	int retry_count=3;
 	
 	memset(rdCmd, 0, cdbsz);
 	sz_ind = 1;
@@ -74,6 +83,8 @@ sg_read (int sg_fd, unsigned char * buff
 	if (diop && *diop)
 	io_hdr.flags |= SG_FLAG_DIRECT_IO;
 
+retry:	
+	memset(senseBuff, 0, SENSE_BUFF_LEN);
 	while (((res = ioctl(sg_fd, SG_IO, &io_hdr)) < 0) && (EINTR == errno));
 
 	if (res < 0) {
@@ -88,6 +99,16 @@ sg_read (int sg_fd, unsigned char * buff
 	    (0 == io_hdr.driver_status)) {
 		return PATH_UP;
 	} else {
+		/*
+	 	 * Retry if UNIT_ATTENTION check condition.
+	 	 */
+		if ((sbb[2]&0xf) == 6) {
+			condlog(4, "readsector0_checker: Read error. "
+				"Sense data are 0x%x/0x%x/0x%x.",
+				sbb[2]&0xf, sbb[12], sbb[13]);
+			if (--retry_count)
+				goto retry;
+		}
 		return PATH_DOWN;
 	}
 }
@@ -95,8 +116,8 @@ sg_read (int sg_fd, unsigned char * buff
 extern int
 readsector0 (struct checker * c)
 {
-	unsigned char buf[512];
 	unsigned char sbuf[SENSE_BUFF_LEN];
+	unsigned char buf[512];
 	int ret;
 
 	ret = sg_read(c->fd, &buf[0], &sbuf[0]);
diff --git a/libcheckers/readsector0.h b/libcheckers/readsector0.h
index 0f5d654..da1aefa 100644
--- a/libcheckers/readsector0.h
+++ b/libcheckers/readsector0.h
@@ -1,8 +1,12 @@
 #ifndef _READSECTOR0_H
 #define _READSECTOR0_H
 
+#define SENSE_BUFF_LEN 32
+
 int readsector0 (struct checker *);
 int readsector0_init (struct checker *);
+unsigned long readsector0_size_scxt (void);
 void readsector0_free (struct checker *);
+int sg_read (int, unsigned char *, unsigned char *); 
 
 #endif /* _READSECTOR0_H */
diff --git a/libcheckers/tur.c b/libcheckers/tur.c
index e79bc0a..b2077c8 100644
--- a/libcheckers/tur.c
+++ b/libcheckers/tur.c
@@ -32,6 +32,11 @@ int tur_init (struct checker * c)
 	return 0;
 }
 
+unsigned long tur_size_scxt (void)
+{
+	return 0;
+}
+
 void tur_free (struct checker * c)
 {
 	return;
diff --git a/libcheckers/tur.h b/libcheckers/tur.h
index a2e8c88..4de44fd 100644
--- a/libcheckers/tur.h
+++ b/libcheckers/tur.h
@@ -3,6 +3,7 @@
 
 int tur (struct checker *);
 int tur_init (struct checker *);
+unsigned long tur_size_scxt (void);
 void tur_free (struct checker *);
 
 #endif /* _TUR_H */
diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
index f21e5bc..e995a98 100644
--- a/libmultipath/discovery.c
+++ b/libmultipath/discovery.c
@@ -610,15 +610,37 @@ static int
 get_state (struct path * pp)
 {
 	struct checker * c = &pp->checker;
+	void * mpctxt = NULL;
+	int size;
 
+#if DAEMON
+	/*
+	 * Avoid initializing path checker for multipathd path checker thread
+	 * until we have linked path to its mpp in order to get mpp shared
+	 * context area for path checkers.
+	 */
+	if (!pp->mpp)
+		return 0;
+#endif
 	if (!checker_selected(c)) {
 		select_checker(pp);
 		if (!checker_selected(c))
 			return 1;
 		checker_set_fd(c, pp->fd);
-		if (checker_init(c))
+		if (pp->mpp) {
+			if (!pp->mpp->mpcontext) {
+				size = checker_size_scxt(c);
+				if (size)
+					mpctxt = pp->mpp->mpcontext =
+							zalloc(size);
+			}
+			else
+				mpctxt = pp->mpp->mpcontext;
+		}
+		if (checker_init(c, mpctxt))
 			return 1;
 	}
+
 	pp->state = checker_check(c);
 	condlog(3, "%s: state = %i", pp->dev, pp->state);
 	if (pp->state == PATH_DOWN)
@@ -706,7 +728,7 @@ pathinfo (struct path *pp, vector hwtabl
 	  * been successfully obtained before.
 	  */
 	if (mask & DI_PRIO &&
-	    (pp->state != PATH_DOWN || pp->priority != PRIO_UNDEF))
+	    (pp->state != PATH_DOWN || pp->priority == PRIO_UNDEF))
 		get_prio(pp);
 
 	if (mask & DI_WWID && !strlen(pp->wwid))
diff --git a/libmultipath/structs.c b/libmultipath/structs.c
index db3f824..d104a09 100644
--- a/libmultipath/structs.c
+++ b/libmultipath/structs.c
@@ -117,8 +117,10 @@ alloc_multipath (void)
 
 	mpp = (struct multipath *)MALLOC(sizeof(struct multipath));
 
-	if (mpp)
+	if (mpp) {
 		mpp->bestpg = 1;
+		mpp->mpcontext = NULL;
+	}
 
 	return mpp;
 }
@@ -180,6 +182,9 @@ free_multipath (struct multipath * mpp, 
 
 	free_pathvec(mpp->paths, free_paths);
 	free_pgvec(mpp->pg, free_paths);
+
+	FREE_PTR(mpp->mpcontext);
+
 	FREE(mpp);
 }
 
diff --git a/libmultipath/structs.h b/libmultipath/structs.h
index 7db7faa..77dd4af 100644
--- a/libmultipath/structs.h
+++ b/libmultipath/structs.h
@@ -154,6 +154,9 @@ struct multipath {
 	unsigned int stat_map_loads;
 	unsigned int stat_total_queueing_time;
 	unsigned int stat_queueing_timeouts;
+
+	/* checkers shared data */
+	void * mpcontext;
 };
 
 struct pathgroup {