diff --git a/tests/zfs-tests/include/default.cfg.in b/tests/zfs-tests/include/default.cfg.in
index 3aed8ebea03a..db70a02a7828 100644
--- a/tests/zfs-tests/include/default.cfg.in
+++ b/tests/zfs-tests/include/default.cfg.in
@@ -1,239 +1,239 @@
 #!/bin/sh
 
 #
 # 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 https://opensource.org/licenses/CDDL-1.0.
 # 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) 2016 by Delphix. All rights reserved.
 # Copyright (c) 2017 Lawrence Livermore National Security, LLC.
 #
 
 . $STF_SUITE/include/commands.cfg
 
 # ZFS Directories
 export ZEDLET_ETC_DIR=${ZEDLET_ETC_DIR:-@sysconfdir@/zfs/zed.d}
 export ZEDLET_LIBEXEC_DIR=${ZEDLET_LIBEXEC_DIR:-@zfsexecdir@/zed.d}
 export ZPOOL_SCRIPT_DIR=${ZPOOL_SCRIPT_DIR:-@sysconfdir@/zfs/zpool.d}
 export ZPOOL_COMPAT_DIR=${ZPOOL_COMPAT_DIR:-@datadir@/zfs/compatibility.d}
 
 # Define run length constants
 export RT_LONG="3"
 export RT_MEDIUM="2"
 export RT_SHORT="1"
 
 # Define macro for zone test
 export ZONE_POOL="zonepool"
 export ZONE_CTR="zonectr"
 
 # ensure we're running in the C locale, since
 # localised messages may result in test failures
 export LC_ALL="C"
 export LANG="C"
 
 #
 # pattern to ignore from 'zpool list'.
 #
 export NO_POOLS="no pools available"
 
 # pattern to ignore from 'zfs list'.
 export NO_DATASETS="no datasets available"
 
 # Default directory used for test files
 # NOTE: remove trailing "/", some functions rely on this to do pattern matching
 export TEST_BASE_DIR="$(dirname ${FILEDIR:-/var/tmp}/.)"
 
 # Default to compression ON
 export COMPRESSION_PROP=on
 
 # Default to using the checksum
 export CHECKSUM_PROP=on
 
 # some common variables used by test scripts :
 export FIO_SCRIPTS=$STF_SUITE/tests/perf/fio
 export PERF_SCRIPTS=$STF_SUITE/tests/perf/scripts
 
 # some test pool names
 export TESTPOOL=testpool
 export TESTPOOL1=testpool1
 export TESTPOOL2=testpool2
 export TESTPOOL3=testpool3
-export PERFPOOL=perfpool
+export PERFPOOL=${PERFPOOL:-perfpool}
 
 # some test file system names
 export TESTFS=testfs
 export TESTFS1=testfs1
 export TESTFS2=testfs2
 export TESTFS3=testfs3
 
 # some test directory names
 export TESTDIR=${TEST_BASE_DIR%%/}/testdir
 export TESTDIR0=${TEST_BASE_DIR%%/}/testdir0
 export TESTDIR1=${TEST_BASE_DIR%%/}/testdir1
 export TESTDIR2=${TEST_BASE_DIR%%/}/testdir2
 
 # some test sub file system names
 export TESTSUBFS=subfs
 export TESTSUBFS1=subfs1
 export TESTSUBFS2=subfs2
 
 # some temp files
 export TEMPFILE=${TEST_BASE_DIR%%/}/tempfile$$
 export TEMPFILE0=${TEST_BASE_DIR%%/}/tempfile0$$
 export TEMPFILE1=${TEST_BASE_DIR%%/}/tempfile1$$
 export TEMPFILE2=${TEST_BASE_DIR%%/}/tempfile2$$
 
 export ZFSROOT=
 
 export TESTSNAP=testsnap
 export TESTSNAP1=testsnap1
 export TESTSNAP2=testsnap2
 export TESTCLONE=testclone
 export TESTCLONE1=testclone1
 export TESTCLONE2=testclone2
 export TESTCLCT=testclct
 export TESTCTR=testctr
 export TESTCTR1=testctr1
 export TESTCTR2=testctr2
 export TESTVOL=testvol
 export TESTVOL1=testvol1
 export TESTVOL2=testvol2
 export TESTFILE0=testfile0
 export TESTFILE1=testfile1
 export TESTFILE2=testfile2
 export TESTBKMARK=testbkmark
 
 export LONGPNAME="poolname50charslong_012345678901234567890123456789"
 export LONGFSNAME="fsysname50charslong_012345678901234567890123456789"
 export SNAPFS="$TESTPOOL/$TESTFS@$TESTSNAP"
 export SNAPFS1="$TESTPOOL/$TESTVOL@$TESTSNAP"
 
 export VOLSIZE=150m
 export BIGVOLSIZE=1eb
 
 # Default to limit disks to be checked
 export MAX_FINDDISKSNUM=6
 
 # Default minimum size for file based vdevs in the test suite
 export MINVDEVSIZE=$((256 * 1024 * 1024))
 
 # Minimum vdev size possible as defined in the OS
 export SPA_MINDEVSIZE=$((64 * 1024 * 1024))
 
 # For iscsi target support
 export ISCSITGTFILE=/tmp/iscsitgt_file
 export ISCSITGT_FMRI=svc:/system/iscsitgt:default
 
 export ZFS_VERSION=5
 export ZFS_ALL_VERSIONS="1 2 3 4 5"
 
 for i in $ZFS_ALL_VERSIONS; do
 	eval 'export ZFS_VERSION_$i="v${i}-fs"'
 done
 
 export MAX_PARTITIONS=8
 
 if [ "@ASAN_ENABLED@" = "yes" ]; then
 	export ASAN_OPTIONS=abort_on_error=true:halt_on_error=true:allocator_may_return_null=true:disable_coredump=false:detect_stack_use_after_return=true:detect_odr_violation=1
 
 	# TODO
 	# disable memory leaks detection
 	# there are quite many of them and they are not as
 	# destructive to CLI programs as they are to daemons
 	export ASAN_OPTIONS="$ASAN_OPTIONS:detect_leaks=false"
 fi
 
 if [ "@UBSAN_ENABLED@" = "yes" ]; then
 	export UBSAN_OPTIONS=abort_on_error=true:halt_on_error=true:print_stacktrace=true
 fi
 
 
 case $(uname) in
 Linux)
 	unpack_opts="--sparse -xf"
 	pack_opts="--sparse -cf"
 	verbose=" -v"
 	unpack_preserve=" -xpf"
 	pack_preserve=" -cpf"
 
 	ZVOL_DEVDIR="/dev/zvol"
 	ZVOL_RDEVDIR="/dev/zvol"
 	DEV_DSKDIR="/dev"
 	DEV_RDSKDIR="/dev"
 	DEV_MPATHDIR="/dev/mapper"
 
 	ZEDLET_DIR="/var/tmp/zed"
 	ZED_LOG="$ZEDLET_DIR/zed.log"
 	ZED_DEBUG_LOG="$ZEDLET_DIR/zed.debug.log"
 	VDEVID_CONF="$ZEDLET_DIR/vdev_id.conf"
 	VDEVID_CONF_ETC="/etc/zfs/vdev_id.conf"
 
 	NEWFS_DEFAULT_FS="ext2"
 	SLICE_PREFIX=""
 	;;
 FreeBSD)
 	unpack_opts="xv"
 	pack_opts="cf"
 	verbose="v"
 	unpack_preserve="xpf"
 	pack_preserve="cpf"
 
 	ZVOL_DEVDIR="/dev/zvol"
 	ZVOL_RDEVDIR="/dev/zvol"
 	DEV_DSKDIR="/dev"
 	DEV_RDSKDIR="/dev"
 	DEV_MPATHDIR="/dev/multipath"
 
 	NEWFS_DEFAULT_FS="ufs"
 	SLICE_PREFIX="p"
 	;;
 *)
 	export AUTO_SNAP=$(svcs -a | \
 	    awk '/auto-snapshot/ && /online/ { print $3 }')
 	# finally, if we're running in a local zone
 	# we take some additional actions
 	if [ "$(zonename 2>/dev/null)" != "global" ]; then
 		reexport_pool
 	fi
 
 	unpack_opts="xv"
 	pack_opts="cf"
 	verbose="v"
 	unpack_preserve="xpf"
 	pack_preserve="cpf"
 
 	ZVOL_DEVDIR="/dev/zvol/dsk"
 	ZVOL_RDEVDIR="/dev/zvol/rdsk"
 	DEV_DSKDIR="/dev/dsk"
 	DEV_RDSKDIR="/dev/rdsk"
 
 	NEWFS_DEFAULT_FS="ufs"
 	SLICE_PREFIX="s"
 	;;
 esac
 export unpack_opts pack_opts verbose unpack_preserve pack_preserve \
        ZVOL_DEVDIR ZVOL_RDEVDIR DEV_DSKDIR DEV_RDSKDIR DEV_MPATHDIR \
        ZEDLET_DIR ZED_LOG ZED_DEBUG_LOG VDEVID_CONF VDEVID_CONF_ETC \
        NEWFS_DEFAULT_FS SLICE_PREFIX