diff --git a/configure.ac b/configure.ac
index b533126afd10..b310307824bd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -273,6 +273,7 @@ AC_CONFIG_FILES([
 	tests/zfs-tests/tests/functional/sparse/Makefile
 	tests/zfs-tests/tests/functional/threadsappend/Makefile
 	tests/zfs-tests/tests/functional/tmpfile/Makefile
+	tests/zfs-tests/tests/functional/trim/Makefile
 	tests/zfs-tests/tests/functional/truncate/Makefile
 	tests/zfs-tests/tests/functional/userquota/Makefile
 	tests/zfs-tests/tests/functional/upgrade/Makefile
diff --git a/tests/runfiles/linux.run b/tests/runfiles/linux.run
index 69e317882850..b7ebcb3e6733 100644
--- a/tests/runfiles/linux.run
+++ b/tests/runfiles/linux.run
@@ -617,6 +617,9 @@ tests = ['sparse_001_pos']
 [tests/functional/tmpfile]
 tests = ['tmpfile_001_pos', 'tmpfile_002_pos', 'tmpfile_003_pos']
 
+[tests/functional/trim]
+tests = ['autotrim_001_pos', 'manualtrim_001_pos']
+
 [tests/functional/truncate]
 tests = ['truncate_001_pos', 'truncate_002_pos']
 
diff --git a/tests/zfs-tests/tests/functional/Makefile.am b/tests/zfs-tests/tests/functional/Makefile.am
index a2d78f520821..bf7a33ae70cd 100644
--- a/tests/zfs-tests/tests/functional/Makefile.am
+++ b/tests/zfs-tests/tests/functional/Makefile.am
@@ -54,6 +54,7 @@ SUBDIRS = \
 	sparse \
 	threadsappend \
 	tmpfile \
+	trim \
 	truncate \
 	upgrade \
 	userquota \
diff --git a/tests/zfs-tests/tests/functional/trim/Makefile.am b/tests/zfs-tests/tests/functional/trim/Makefile.am
new file mode 100644
index 000000000000..a379bf898fd5
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/trim/Makefile.am
@@ -0,0 +1,8 @@
+pkgdatadir = $(datadir)/@PACKAGE@/zfs-tests/tests/functional/trim
+dist_pkgdata_SCRIPTS = \
+	setup.ksh \
+	trim.cfg \
+	trim.kshlib \
+	cleanup.ksh \
+	autotrim_001_pos.ksh \
+	manualtrim_001_pos.ksh
diff --git a/tests/zfs-tests/tests/functional/trim/autotrim_001_pos.ksh b/tests/zfs-tests/tests/functional/trim/autotrim_001_pos.ksh
new file mode 100755
index 000000000000..fc74bb7bf570
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/trim/autotrim_001_pos.ksh
@@ -0,0 +1,114 @@
+#!/bin/ksh -p
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+#
+# Copyright (c) 2013, 2014 by Delphix. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+. $STF_SUITE/tests/functional/trim/trim.cfg
+. $STF_SUITE/tests/functional/trim/trim.kshlib
+
+set_tunable zfs_trim_min_ext_sz 4096
+set_tunable zfs_txgs_per_trim 2
+
+function getsizemb
+{
+	typeset rval
+
+	rval=$(du --block-size 1048576 -s "$1" | sed -e 's;[ 	].*;;')
+	echo -n "$rval"
+}
+
+function checkvdevs
+{
+	typeset vd sz
+
+	for vd in $VDEVS; do
+		sz=$(getsizemb $vd)
+		log_note Size of $vd is $sz MB
+		log_must test $sz -le $SHRUNK_SIZE_MB
+	done
+}
+
+function txgs
+{
+	typeset x
+
+	# Run some txgs in order to let autotrim do its work.
+	#
+	for x in 1 2 3; do
+		log_must zfs snapshot $TRIMPOOL@snap
+		log_must zfs destroy  $TRIMPOOL@snap
+		log_must zfs snapshot $TRIMPOOL@snap
+		log_must zfs destroy  $TRIMPOOL@snap
+	done
+}
+
+#
+# Check various pool geometries:  Create the pool, fill it, remove the test file,
+# run some txgs, export the pool and verify that the vdevs shrunk.
+#
+
+#
+# raidz
+#
+for z in 1 2 3; do
+	setupvdevs
+	log_must zpool create -f $TRIMPOOL raidz$z $VDEVS
+	log_must zpool set autotrim=on $TRIMPOOL
+	log_must file_write -o create -f "/$TRIMPOOL/$TESTFILE" -b $BLOCKSIZE -c $NUM_WRITES -d R -w
+	log_must rm "/$TRIMPOOL/$TESTFILE"
+	txgs
+	log_must zpool export $TRIMPOOL
+	checkvdevs
+done
+
+#
+# mirror
+#
+setupvdevs
+log_must zpool create -f $TRIMPOOL mirror $MIRROR_VDEVS_1 mirror $MIRROR_VDEVS_2
+log_must zpool set autotrim=on $TRIMPOOL
+log_must file_write -o create -f "/$TRIMPOOL/$TESTFILE" -b $BLOCKSIZE -c $NUM_WRITES -d R -w
+log_must rm "/$TRIMPOOL/$TESTFILE"
+txgs
+log_must zpool export $TRIMPOOL
+checkvdevs
+
+#
+# stripe
+#
+setupvdevs
+log_must zpool create -f $TRIMPOOL $STRIPE_VDEVS
+log_must zpool set autotrim=on $TRIMPOOL
+log_must file_write -o create -f "/$TRIMPOOL/$TESTFILE" -b $BLOCKSIZE -c $NUM_WRITES -d R -w
+log_must rm "/$TRIMPOOL/$TESTFILE"
+txgs
+log_must zpool export $TRIMPOOL
+checkvdevs
+
+log_pass TRIM successfully shrunk vdevs
diff --git a/tests/zfs-tests/tests/functional/trim/cleanup.ksh b/tests/zfs-tests/tests/functional/trim/cleanup.ksh
new file mode 100755
index 000000000000..e8d1515e660a
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/trim/cleanup.ksh
@@ -0,0 +1,31 @@
+#!/bin/ksh -p
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+
+. $STF_SUITE/include/libtest.shlib
+. $STF_SUITE/tests/functional/trim/trim.cfg
+
+rm -f $VDEVS
diff --git a/tests/zfs-tests/tests/functional/trim/manualtrim_001_pos.ksh b/tests/zfs-tests/tests/functional/trim/manualtrim_001_pos.ksh
new file mode 100755
index 000000000000..7603a85cfd26
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/trim/manualtrim_001_pos.ksh
@@ -0,0 +1,100 @@
+#!/bin/ksh -p
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+#
+# Copyright (c) 2013, 2014 by Delphix. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+. $STF_SUITE/tests/functional/trim/trim.cfg
+. $STF_SUITE/tests/functional/trim/trim.kshlib
+
+set_tunable zfs_trim_min_ext_sz 4096
+
+function getsizemb
+{
+	typeset rval
+
+	rval=$(du --block-size 1048576 -s "$1" | sed -e 's;[ 	].*;;')
+	echo -n "$rval"
+}
+
+function checkvdevs
+{
+	typeset vd sz
+
+	for vd in $VDEVS; do
+		sz=$(getsizemb $vd)
+		log_note Size of $vd is $sz MB
+		log_must test $sz -le $SHRUNK_SIZE_MB
+	done
+}
+
+function dotrim
+{
+	log_must rm "/$TRIMPOOL/$TESTFILE"
+	log_must zpool export $TRIMPOOL
+	log_must zpool import -d $VDEVDIR $TRIMPOOL
+	log_must zpool trim $TRIMPOOL
+	sleep 5
+	log_must zpool export $TRIMPOOL
+}
+
+#
+# Check various pool geometries:  Create the pool, fill it, remove the test file,
+# perform a manual trim, export the pool and verify that the vdevs shrunk.
+#
+
+#
+# raidz
+#
+for z in 1 2 3; do
+	setupvdevs
+	log_must zpool create -f $TRIMPOOL raidz$z $VDEVS
+	log_must file_write -o create -f "/$TRIMPOOL/$TESTFILE" -b $BLOCKSIZE -c $NUM_WRITES -d R -w
+	dotrim
+	checkvdevs
+done
+
+#
+# mirror
+#
+setupvdevs
+log_must zpool create -f $TRIMPOOL mirror $MIRROR_VDEVS_1 mirror $MIRROR_VDEVS_2
+log_must file_write -o create -f "/$TRIMPOOL/$TESTFILE" -b $BLOCKSIZE -c $NUM_WRITES -d R -w
+dotrim
+checkvdevs
+
+#
+# stripe
+#
+setupvdevs
+log_must zpool create -f $TRIMPOOL $STRIPE_VDEVS
+log_must file_write -o create -f "/$TRIMPOOL/$TESTFILE" -b $BLOCKSIZE -c $NUM_WRITES -d R -w
+dotrim
+checkvdevs
+
+log_pass Manual TRIM successfully shrunk vdevs
diff --git a/tests/zfs-tests/tests/functional/trim/setup.ksh b/tests/zfs-tests/tests/functional/trim/setup.ksh
new file mode 100755
index 000000000000..feb9ef2ed7ea
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/trim/setup.ksh
@@ -0,0 +1,36 @@
+#!/bin/ksh -p
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+
+#
+# Copyright (c) 2013 by Delphix. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+. $STF_SUITE/tests/functional/trim/trim.cfg
+. $STF_SUITE/tests/functional/trim/trim.kshlib
+
+log_pass TRIM setup succeeded
diff --git a/tests/zfs-tests/tests/functional/trim/trim.cfg b/tests/zfs-tests/tests/functional/trim/trim.cfg
new file mode 100644
index 000000000000..a24ee4fb0fe6
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/trim/trim.cfg
@@ -0,0 +1,60 @@
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+
+#
+# Copyright (c) 2013 by Delphix. All rights reserved.
+#
+
+#
+# Parameters
+#
+TRIMPOOL=trimpool
+VDEVDIR="/tmp"
+VDEVS="/tmp/trim1.dev /tmp/trim2.dev /tmp/trim3.dev /tmp/trim4.dev /tmp/trim5.dev"
+VDEV_SIZE=128m
+TESTFILE=testfile
+SHRUNK_SIZE_MB=12
+
+NUM_WRITES=2048
+BLOCKSIZE=65536
+
+#
+# Computed values and parameters
+#
+function get_mirror_vdevs
+{
+	set -- $VDEVS
+	MIRROR_VDEVS_1="$1 $2"
+	MIRROR_VDEVS_2="$3 $4"
+}
+get_mirror_vdevs
+	
+function get_stripe_vdevs
+{
+	set -- $VDEVS
+	STRIPE_VDEVS="$1 $2 $3 $4"
+}
+get_stripe_vdevs
diff --git a/tests/zfs-tests/tests/functional/trim/trim.kshlib b/tests/zfs-tests/tests/functional/trim/trim.kshlib
new file mode 100644
index 000000000000..041c1f0754b7
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/trim/trim.kshlib
@@ -0,0 +1,35 @@
+#
+# This file and its contents are supplied under the terms of the
+# Common Development and Distribution License ("CDDL"), version 1.0.
+# You may only use this file in accordance with the terms of version
+# 1.0 of the CDDL.
+#
+# A full copy of the text of the CDDL should have accompanied this
+# source.  A copy of the CDDL is also available via the Internet at
+# http://www.illumos.org/license/CDDL.
+#
+
+function set_tunable
+{
+	typeset tunable="$1"
+	typeset value="$2"
+	typeset zfs_tunables="/sys/module/zfs/parameters"
+
+	[[ -z "$tunable" ]] && return 1
+	[[ -z "$value" ]] && return 1
+	[[ -f "$zfs_tunables/$tunable" ]] || return 1
+
+	echo -n "$value" > "$zfs_tunables/$tunable"
+	return "$?"
+}
+
+function find_scsi_debug
+{
+	grep -H scsi_debug /sys/block/*/device/model | $AWK -F/ '{print $4}' | tr '\n' ' '
+}
+
+function setupvdevs
+{
+	log_must rm -f $VDEVS
+	log_must truncate -s 192m $VDEVS
+}