Merge pull request #543 from ceph/min_free_kbytes

ceph-common: calculate vm.min_free_kbytes

group_vars/all.sample

@@ -283,4 +283,4 @@ dummy:
 #  - { name: fs.file-max, value: 26234859 }
 #  - { name: vm.zone_reclaim_mode, value: 0 }
 #  - { name: vm.vfs_cache_pressure, value: 50 }
-#  - { name: vm.min_free_kbytes, value: 4194303 }
+#  - { name: vm.min_free_kbytes, value: "{{ vm_min_free_kbytes }}" }

roles/ceph-common/defaults/main.yml

@@ -295,7 +295,7 @@ os_tuning_params:
   - { name: fs.file-max, value: 26234859 }
   - { name: vm.zone_reclaim_mode, value: 0 }
   - { name: vm.vfs_cache_pressure, value: 50 }
-  - { name: vm.min_free_kbytes, value: 4194303 }
+  - { name: vm.min_free_kbytes, value: "{{ vm_min_free_kbytes }}" }
 
 
 ##########

roles/ceph-common/tasks/misc/system_tuning.yml

@@ -16,6 +16,14 @@
   failed_when: false
   when: disable_swap
 
+- name: get default vm.min_free_kbytes
+  command: sysctl -b vm.min_free_kbytes
+  register: default_vm_min_free_kbytes
+
+- name: define vm.min_free_kbytes
+  set_fact:
+    vm_min_free_kbytes: "{{ 4194303 if ansible_memtotal_mb >= 49152 else default_vm_min_free_kbytes.stdout }}"
+
 - name: apply operating system tuning
   sysctl:
     name: "{{ item.name }}"