diff --git a/xCAT-server-2.0/lib/xcat/plugins/iscsi.pm b/xCAT-server-2.0/lib/xcat/plugins/iscsi.pm
index 295cb25d5..8d8fe36e7 100644
--- a/xCAT-server-2.0/lib/xcat/plugins/iscsi.pm
+++ b/xCAT-server-2.0/lib/xcat/plugins/iscsi.pm
@@ -54,7 +54,7 @@ sub process_request {
       return;
    }
    @ARGV=@{$request->{arg}};
-   my $lunsize = 2048;
+   my $lunsize = 4096;
    GetOptions(
       "size|s=i" => \$lunsize,
    );