Add tuning for Ceph OSDs

group_vars/default/pvc.yml

@@ -72,6 +72,12 @@ pvc_asn: "65500"
 pvc_routers:
   - "192.168.100.1"
 
+# Ceph OSD tuning
+# > Uncomment in low-memory situation (nodes with <32GB RAM).
+# > These options are *only* applied at cluster bootstrap and cannot be changed later.
+# OSD memory limit - 939524096 (~900MB) is the lowest possible value; default is 4GB.
+#pvc_osd_memory_limit: 939524096
+
 # Node list
 # > Every node configured with this playbook must be specified in this list.
 pvc_nodes:

roles/pvc/tasks/ceph/bootstrap.yml

@@ -68,9 +68,19 @@
     - "osd journal size = 2"
     - "osd pool default size = 3"
     - "osd pool default min size = 2"
-    - "osd pool default pg num = 512"
-    - "osd pool default pgp num = 512"
+    - "osd pool default pg num = 256"
+    - "osd pool default pgp num = 256"
     - "osd crush chooseleaf type = 1"
+    - "bluestore cache autotune = true"
+
+- name: add memory limit if requested
+  lineinfile:
+    dest: /tmp/ceph-bootstrap/ceph.conf
+    line: "{{ item }}"
+    state: present
+  with_items:
+    - "osd memory target = {{ pvc_osd_memory_limit }}"
+  when: pvc_osd_memory_limit is defined
 
 - name: collect bootstrapped Ceph files into the role
   fetch: