01/02: install: Do not cache lookup failures.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository guix.

commit c96ba2cf5efc0ee5c10f0a49aeaa9a45a84de7ed
Author: Ludovic Courtès <address@hidden>
Date:   Wed Feb 10 21:21:38 2016 +0100

    install: Do not cache lookup failures.
    
    Possibly fixes <http://bugs.gnu.org/22209>.
    
    * gnu/system/install.scm (%nscd-minimal-caches)[negative-time-to-live]:
    Set to zero.
---
 gnu/system/install.scm |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/gnu/system/install.scm b/gnu/system/install.scm
index 0cfc8fa..6cde649 100644
--- a/gnu/system/install.scm
+++ b/gnu/system/install.scm
@@ -237,7 +237,12 @@ the user's target storage device rather than on the RAM 
disk."
   ;; Minimal in-memory caching policy for nscd.
   (list (nscd-cache (database 'hosts)
                     (positive-time-to-live (* 3600 12))
-                    (negative-time-to-live 20)
+
+                    ;; Do not cache lookup failures at all since they are
+                    ;; quite likely (for instance when someone tries to ping a
+                    ;; host before networking is functional.)
+                    (negative-time-to-live 0)
+
                     (persistent? #f)
                     (max-database-size (* 5 (expt 2 20)))))) ;5 MiB