[3.0] 73efe81 Document the storage.<name>.* VCL variables.

[Martin Blix Grydeland]

commit 73efe8191aa764e3084d2a2bd738a60d7af964bc
Author: Martin Blix Grydeland <martin at varnish-software.com>
Date:   Mon Jun 2 14:46:36 2014 +0200

    Document the storage.<name>.* VCL variables.
    
    Fixes: #1514

diff --git a/doc/sphinx/reference/vcl.rst b/doc/sphinx/reference/vcl.rst
index ffd7c0c..b348e9d 100644
--- a/doc/sphinx/reference/vcl.rst
+++ b/doc/sphinx/reference/vcl.rst
@@ -903,6 +903,21 @@ resp.response
 resp.http.header
   The corresponding HTTP header.
 
+The following read-only variables report on the state of a named
+storage stevedore. Not all stevedores implement all of the variables:
+
+storage.<name>.free_space
+  Free space in bytes on the named stevedore. Only the malloc
+  stevedore implements this.
+
+storage.<name>.used_space
+  Used space in bytes on the named stevedore. Only the malloc
+  stevedore implements this.
+
+storage.<name>.happy
+  Health status for the named stevedore. None of the stevedores
+  implements this.
+
 Values may be assigned to variables using the set keyword:
 ::