diff --git a/xcache.ini b/xcache.ini
index cf46832..55f264c 100644
--- a/xcache.ini
+++ b/xcache.ini
@@ -39,6 +39,12 @@ xcache.var_ttl   =             0
 xcache.var_maxttl   =          0
 xcache.var_gc_interval =     300
 
+; mode:0, const string specified by xcache.var_namespace
+; mode:1, $_SERVER[xcache.var_namespace]
+; mode:2, uid or gid (specified by xcache.var_namespace)
+xcache.var_namespace_mode =    0
+xcache.var_namespace =        ""
+
 ; N/A for /dev/zero
 xcache.readonly_protection = Off
 ; for *nix, xcache.mmap_path is a file path, not directory. (auto create/overwrite)