diff --git a/cmd/zpios/zpios_main.c b/cmd/zpios/zpios_main.c
index 0505ad5db4..662a7b8ecc 100644
--- a/cmd/zpios/zpios_main.c
+++ b/cmd/zpios/zpios_main.c
@@ -45,7 +45,7 @@
 #include "zpios.h"
 
 static const char short_opt[] = "t:l:h:e:n:i:j:k:o:m:q:r:c:a:b:g:s:A:B:C:"
-                                "L:p:xP:R:G:I:N:T:VzOHv?";
+                                "L:p:xP:R:G:I:N:T:VzOfHv?";
 static const struct option long_opt[] = {
 	{"threadcount",         required_argument, 0, 't' },
 	{"threadcount_low",     required_argument, 0, 'l' },
@@ -79,6 +79,7 @@ static const struct option long_opt[] = {
 	{"verify",              no_argument,       0, 'V' },
 	{"zerocopy",            no_argument,       0, 'z' },
 	{"nowait",              no_argument,       0, 'O' },
+	{"noprefetch",          no_argument,       0, 'f' },
 	{"human-readable",      no_argument,       0, 'H' },
 	{"verbose",             no_argument,       0, 'v' },
 	{"help",                no_argument,       0, '?' },
@@ -127,6 +128,7 @@ usage(void)
 	        "	--verify            -V\n"
 	        "	--zerocopy          -z\n"
 	        "	--nowait            -O\n"
+		"	--noprefetch        -f\n"
 	        "	--human-readable    -H\n"
 	        "	--verbose           -v    =increase verbosity\n"
 	        "	--help              -?    =this help\n\n");
@@ -283,6 +285,9 @@ args_init(int argc, char **argv)
 		case 'O': /* --nowait */
 			args->flags |= DMU_WRITE_NOWAIT;
 			break;
+		case 'f': /* --noprefetch */
+			args->flags |= DMU_READ_NOPF;
+			break;
 		case 'H': /* --human-readable */
 			args->human_readable = 1;
 			break;
diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c
index c0137215b9..ac0f51d8e2 100644
--- a/module/zfs/dmu.c
+++ b/module/zfs/dmu.c
@@ -601,13 +601,6 @@ dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 	return (err);
 }
 
-int
-dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
-    void *buf)
-{
-	return dmu_read_impl(os, object, offset, size, buf, 0);
-}
-
 void
 dmu_write_impl(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
     const void *buf, dmu_tx_t *tx, int flags)
@@ -651,6 +644,13 @@ dmu_write_impl(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 	dmu_buf_rele_array(dbp, numbufs, FTAG);
 }
 
+void
+dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
+    const void *buf, dmu_tx_t *tx)
+{
+	dmu_write_impl(os, object, offset, size, buf, tx, 0);
+}
+
 void
 dmu_prealloc(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
     dmu_tx_t *tx)
@@ -672,13 +672,6 @@ dmu_prealloc(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 	dmu_buf_rele_array(dbp, numbufs, FTAG);
 }
 
-void
-dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
-    const void *buf, dmu_tx_t *tx)
-{
-	dmu_write_impl(os, object, offset, size, buf, tx, 0);
-}
-
 #if defined(_KERNEL) && defined(HAVE_UIO_RW)
 int
 dmu_read_uio(objset_t *os, uint64_t object, uio_t *uio, uint64_t size)
@@ -1299,7 +1292,6 @@ dmu_fini(void)
 #if defined(_KERNEL) && defined(HAVE_SPL)
 EXPORT_SYMBOL(dmu_bonus_hold);
 EXPORT_SYMBOL(dmu_free_range);
-EXPORT_SYMBOL(dmu_read_impl);
 EXPORT_SYMBOL(dmu_read);
 EXPORT_SYMBOL(dmu_write_impl);
 EXPORT_SYMBOL(dmu_write);
diff --git a/module/zfs/include/sys/dmu.h b/module/zfs/include/sys/dmu.h
index 562a9251de..e976fc8b1c 100644
--- a/module/zfs/include/sys/dmu.h
+++ b/module/zfs/include/sys/dmu.h
@@ -156,10 +156,8 @@ void zfs_znode_byteswap(void *buf, size_t size);
  * The maximum number of bytes that can be accessed as part of one
  * operation, including metadata.
  */
-#define DMU_MAX_ACCESS		(10<<20) /* 10MB */
-#define DMU_MAX_DELETEBLKCNT	(20480) /* ~5MB of indirect blocks */
-#define DMU_WRITE_ZEROCOPY	0x0001
-#define DMU_READ_ZEROCOPY	0x0002
+#define	DMU_MAX_ACCESS		(10<<20) /* 10MB */
+#define	DMU_MAX_DELETEBLKCNT	(20480) /* ~5MB of indirect blocks */
 
 #define	DMU_USERUSED_OBJECT	(-1ULL)
 #define	DMU_GROUPUSED_OBJECT	(-2ULL)
@@ -481,6 +479,8 @@ int dmu_free_object(objset_t *os, uint64_t object);
  */
 #define	DMU_READ_PREFETCH	0 /* prefetch */
 #define	DMU_READ_NO_PREFETCH	1 /* don't prefetch */
+#define	DMU_READ_ZEROCOPY	2 /* zerocopy on read (test) */
+#define	DMU_WRITE_ZEROCOPY	4 /* zerocopy on write (test) */
 int dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 	void *buf, uint32_t flags);
 void dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
diff --git a/module/zpios/include/zpios-ctl.h b/module/zpios/include/zpios-ctl.h
index abe4b814bf..25a04bba01 100644
--- a/module/zpios/include/zpios-ctl.h
+++ b/module/zpios/include/zpios-ctl.h
@@ -46,14 +46,15 @@
 
 #define DMU_IO				0x01
 
-#define DMU_WRITE			0x01
-#define DMU_READ			0x02
-#define DMU_VERIFY			0x04
-#define DMU_REMOVE			0x08
-#define DMU_FPP				0x10
-#define DMU_WRITE_ZC			0x20 /* Incompatible with DMU_VERIFY */
-#define DMU_READ_ZC			0x40 /* Incompatible with DMU_VERIFY */
-#define DMU_WRITE_NOWAIT		0x80
+#define DMU_WRITE			0x0001
+#define DMU_READ			0x0002
+#define DMU_VERIFY			0x0004
+#define DMU_REMOVE			0x0008
+#define DMU_FPP				0x0010
+#define DMU_WRITE_ZC			0x0020 /* Incompatible w/DMU_VERIFY */
+#define DMU_READ_ZC			0x0040 /* Incompatible w/DMU_VERIFY */
+#define DMU_WRITE_NOWAIT		0x0080
+#define DMU_READ_NOPF			0x0100
 
 #define ZPIOS_NAME_SIZE			16
 #define ZPIOS_PATH_SIZE			128
diff --git a/module/zpios/zpios.c b/module/zpios/zpios.c
index fb508d7bbf..bf811c67ae 100644
--- a/module/zpios/zpios.c
+++ b/module/zpios/zpios.c
@@ -469,7 +469,10 @@ zpios_dmu_read(run_args_t *run_args, objset_t *os, uint64_t object,
 	if (run_args->flags & DMU_READ_ZC)
 		flags |= DMU_READ_ZEROCOPY;
 
-	return dmu_read_impl(os, object, offset, size, buf, flags);
+	if (run_args->flags & DMU_READ_NOPF)
+		flags |= DMU_READ_NO_PREFETCH;
+
+	return dmu_read(os, object, offset, size, buf, flags);
 }
 
 static int
diff --git a/scripts/zpios-survey.sh b/scripts/zpios-survey.sh
index 2a3a33033e..6c5e1935b3 100755
--- a/scripts/zpios-survey.sh
+++ b/scripts/zpios-survey.sh
@@ -50,16 +50,16 @@ zpios_survey_base() {
 
 # Disable ZFS's prefetching.  For some reason still not clear to me
 # current prefetching policy is quite bad for a random workload.
-# Allowint the algorithm to detect a random workload and not do 
+# Allowing the algorithm to detect a random workload and not do 
 # anything may be the way to address this issue.
 zpios_survey_prefetch() {
 	TEST_NAME="${ZPOOL_CONFIG}+${ZPIOS_TEST}+prefetch"
 	print_header ${TEST_NAME}
 
 	./zfs.sh ${VERBOSE_FLAG}               \
-		zfs="zfs_prefetch_disable=1" | \
 		tee -a ${ZPIOS_SURVEY_LOG}
 	./zpios.sh ${VERBOSE_FLAG} -c ${ZPOOL_CONFIG} -t ${ZPIOS_TEST} | \
+		-o "--noprefetch" |                                      \
 		tee -a ${ZPIOS_SURVEY_LOG}
 	./zfs.sh -u ${VERBOSE_FLAG} | \
 		tee -a ${ZPIOS_SURVEY_LOG}
@@ -144,12 +144,11 @@ zpios_survey_all() {
 	print_header ${TEST_NAME}
 
 	./zfs.sh ${VERBOSE_FLAG}                \  
-		zfs="zfs_prefetch_disable=1"    \
 		zfs="zfs_vdev_max_pending=1024" \
 		zfs="zio_bulk_flags=0x100" |    \
 		tee -a ${ZPIOS_SURVEY_LOG}
 	./zpios.sh ${VERBOSE_FLAG} -c ${ZPOOL_CONFIG} -t ${ZPIOS_TEST} \
-		-o "--zerocopy"                                        \
+		-o "--noprefetch --zerocopy"                           \
 		-s "set checksum=off" |                                \
 		tee -a ${ZPIOS_SURVEY_LOG}
 	./zfs.sh -u ${VERBOSE_FLAG} | \