bundles/unbound: better caching

bundles/unbound/files/unbound.conf

@@ -27,7 +27,12 @@ server:
     access-control: ::1 allow
 % endif
 
+    msg-cache-size: ${cache_size}
+    msg-cache-slabs: ${cache_slabs}
+    rrset-cache-size: ${cache_size}
+    rrset-cache-slabs: ${cache_slabs}
     cache-max-ttl: ${max_ttl}
+    cache-max-negative-ttl: 600
 
     use-syslog: yes
     log-queries: no

bundles/unbound/metadata.py

@@ -17,15 +17,19 @@ defaults = {
     },
     'unbound': {
         'max_ttl': 3600,
+        'cache_size': '512M',
     },
 }
 
 
 @metadata_reactor
-def cpu_cores_to_threads(metadata):
+def cpu_cores_to_config_values(metadata):
+    num_cpus = metadata.get('vm/cpu', 1)
+
     return {
         'unbound': {
-            'threads': metadata.get('vm/cpu', 1)*2,
+            'threads': num_cpus*2,
+            'cache_slabs': 2**(num_cpus-1).bit_length(),
         },
     }