--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/usr/src/test/zfs-tests/tests/functional/persist_l2arc/persist_l2arc_007_pos.ksh	Thu Jul 30 18:40:44 2020 -0500
@@ -0,0 +1,95 @@
+#!/bin/ksh -p
+#
+# CDDL HEADER START
+#
+# 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.
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright (c) 2020, George Amanakis. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+. $STF_SUITE/tests/functional/persist_l2arc/persist_l2arc.cfg
+
+#
+# DESCRIPTION:
+#	Off/onlining an L2ARC device results in rebuilding L2ARC, vdev present.
+#
+# STRATEGY:
+#	1. Create pool with a cache device.
+#	2. Create a random file in that pool and random read for 30 sec.
+#	3. Read the amount of log blocks written from the header of the
+#		L2ARC device.
+#	4. Offline the L2ARC device.
+#	5. Online the L2ARC device.
+#	6. Read the amount of log blocks rebuilt in arcstats and compare to
+#		(3).
+#	7. Check if the labels of the L2ARC device are intact.
+#
+
+verify_runnable "global"
+
+log_assert "Off/onlining an L2ARC device results in rebuilding L2ARC, vdev present."
+
+function cleanup
+{
+	if poolexists $TESTPOOL ; then
+		destroy_pool $TESTPOOL
+	fi
+
+	log_must set_tunable32 l2arc_noprefetch $noprefetch
+	log_must set_tunable32 l2arc_rebuild_blocks_min_l2size \
+		$rebuild_blocks_min_l2size
+}
+log_onexit cleanup
+
+# l2arc_noprefetch is set to 0 to let L2ARC handle prefetches
+typeset noprefetch=$(get_tunable l2arc_noprefetch)
+typeset rebuild_blocks_min_l2size=$(get_tunable l2arc_rebuild_blocks_min_l2size)
+log_must set_tunable32 l2arc_noprefetch 0
+log_must set_tunable32 l2arc_rebuild_blocks_min_l2size 0
+
+typeset fill_mb=800
+typeset cache_sz=$(( floor($fill_mb / 2) ))
+export FILE_SIZE=$(( floor($fill_mb / $NUMJOBS) ))M
+
+log_must truncate -s ${cache_sz}M $VDEV_CACHE
+
+log_must zpool create -f $TESTPOOL $VDEV cache $VDEV_CACHE
+
+log_must fio $FIO_SCRIPTS/mkfiles.fio
+log_must fio $FIO_SCRIPTS/random_reads.fio
+
+log_must zpool offline $TESTPOOL $VDEV_CACHE
+
+sleep 10
+
+typeset l2_rebuild_log_blk_start=$(get_arcstat l2_rebuild_log_blks)
+
+typeset l2_dh_log_blk=$(zdb -l $VDEV_CACHE | grep log_blk_count | \
+	awk '{print $2}')
+
+log_must zpool online $TESTPOOL $VDEV_CACHE
+
+sleep 10
+
+typeset l2_rebuild_log_blk_end=$(get_arcstat l2_rebuild_log_blks)
+
+log_must test $l2_dh_log_blk -eq $(( $l2_rebuild_log_blk_end - $l2_rebuild_log_blk_start ))
+log_must test $l2_dh_log_blk -gt 0
+
+log_must zdb -lq $VDEV_CACHE
+
+log_must zpool destroy -f $TESTPOOL
+
+log_pass "Off/onlining an L2ARC device results in rebuilding L2ARC, vdev present."