Merge pull request #126 from jt-edb/merge_3_0_0_master_2

Autotuning: configure vm.overcommit_ratio

VERSION

@@ -1 +1 @@
-3.0.2
+3.0.3

roles/autotuning/tasks/setup_tuned.yml

@@ -1,4 +1,25 @@
 ---
+# With vm.swapiness=1 and vm.overcommit_memory=2, vm.overcommit_ratio should
+# allow the system to use the entire memory available.
+#
+#                    RAM * vm.overcommit_ratio
+# Max Alloc = SWAP + -------------------------
+#                              100
+#
+# If we want to allow the system to allocate the entire memory (Max Alloc =
+# RAM), then, overcommit_ratio is calculated as below:
+#
+#                        RAM - SWAP
+# vm.overcommit_ratio = ------------ * 100
+#                           RAM
+#
+# We ensure a minimum value of 50. This is usefull for the case when the amount
+# of swap memory is ridiculous higher than the RAM size
+- name: Set vm_overcommit_ratio
+  set_fact:
+    vm_overcommit_ratio: >-
+      {{ [ ((ansible_memtotal_mb - ansible_swaptotal_mb) / ansible_memtotal_mb * 100) | int,
+           50 ] | max }}
 
 - name: Set the variable tuned_disk_elevator for CentOS/RHEL 7
   set_fact:

roles/autotuning/templates/tuned.conf.template

@@ -10,6 +10,7 @@ elevator={{ tuned_disk_elevator }}
 [sysctl]
 {% if 'pemserver' not in group_names %}
 vm.overcommit_memory=2
+vm.overcommit_ratio={{ vm_overcommit_ratio }}
 vm.swappiness=1
 {% endif %}
 vm.dirty_ratio=30