diff --git a/mysql-test/lib/My/File/Path.pm b/mysql-test/lib/My/File/Path.pm
index d60027c909e..fd3cf6dd61c 100644
--- a/mysql-test/lib/My/File/Path.pm
+++ b/mysql-test/lib/My/File/Path.pm
@@ -34,7 +34,7 @@ use strict;
 
 use Exporter;
 use base "Exporter";
-our @EXPORT= qw /rmtree mkpath copytree/;
+our @EXPORT= qw /rmtree mkpath copytree make_readonly/;
 
 use File::Find;
 use File::Copy;
@@ -184,6 +184,10 @@ sub copytree {
     # Only copy plain files
     next unless -f "$from_dir/$_";
     copy("$from_dir/$_", "$to_dir/$_");
+    if (!$use_umask)
+    {
+      chmod(0666, "$to_dir/$_");
+    }
   }
   closedir(DIR);
 
@@ -193,4 +197,29 @@ sub copytree {
   }
 }
 
+
+sub make_readonly {
+  my ($dir) = @_;
+
+  die "Usage: make_readonly(<dir>])"
+    unless @_ == 1;
+
+  opendir(DIR, "$dir")
+    or croak("Can't find $dir$!");
+  for(readdir(DIR)) {
+
+    next if "$_" eq "." or "$_" eq "..";
+
+    if ( -d "$dir/$_" )
+    {
+      make_readonly("$dir/$_");
+      next;
+    }
+
+    # Only copy plain files
+    next unless -f "$dir/$_";
+    chmod 0444, "$dir/$_";
+  }
+  closedir(DIR);
+}
 1;
diff --git a/mysql-test/lib/My/SafeProcess/Base.pm b/mysql-test/lib/My/SafeProcess/Base.pm
index 818e6e34e11..1cd01cb0ca9 100644
--- a/mysql-test/lib/My/SafeProcess/Base.pm
+++ b/mysql-test/lib/My/SafeProcess/Base.pm
@@ -40,7 +40,7 @@ our @EXPORT= qw(create_process);
 #   Retry a couple of times if fork returns EAGAIN
 #
 sub _safe_fork {
-  my $retries= 5;
+  my $retries= 100;
   my $pid;
 
  FORK:
diff --git a/mysql-test/mysql-test-run.pl b/mysql-test/mysql-test-run.pl
index da5e33428a9..0513bc209ad 100755
--- a/mysql-test/mysql-test-run.pl
+++ b/mysql-test/mysql-test-run.pl
@@ -401,8 +401,11 @@ sub main {
   my $tests= collect_test_cases($opt_reorder, $opt_suites, \@opt_cases, \@opt_skip_test_list);
   mark_time_used('collect');
 
-  mysql_install_db(default_mysqld(), "$opt_vardir/install.db") unless using_extern();
-
+  if (!using_extern())
+  {
+    mysql_install_db(default_mysqld(), "$opt_vardir/install.db");
+    make_readonly("$opt_vardir/install.db");
+  }
   if ($opt_dry_run)
   {
     for (@$tests) {
diff --git a/storage/spider/mysql-test/spider/bugfix/t/mdev_30370.test b/storage/spider/mysql-test/spider/bugfix/t/mdev_30370.test
index 788ea2323f7..99e56ab062a 100644
--- a/storage/spider/mysql-test/spider/bugfix/t/mdev_30370.test
+++ b/storage/spider/mysql-test/spider/bugfix/t/mdev_30370.test
@@ -2,4 +2,7 @@
 --echo # MDEV-30370 mariadbd hangs when running with --wsrep-recover and --plugin-load-add=ha_spider.so
 --echo #
 
---exec $MYSQLD_BOOTSTRAP_CMD --wsrep-recover --plugin-load-add=ha_spider.so
+let $MYSQLD_DATADIR=$MYSQLTEST_VARDIR/mdev_30370;
+--mkdir $MYSQLD_DATADIR
+--exec $MYSQLD_BOOTSTRAP_CMD --wsrep-recover --plugin-load-add=ha_spider.so --datadir=$MYSQLD_DATADIR
+--rmdir $MYSQLD_DATADIR