set default arc to 20%, attempt to fix data pool creation idempotence

globals.yaml

@@ -1,7 +1,7 @@
 ---
 username: jlay  # user for 'create-user' role
-zfs_disk: /dev/sdb
-zfs_arc_size_mb: "{{ (ansible_memtotal_mb * 0.50)|int|abs }}"
+zfs_disk: /dev/vdb
+zfs_arc_size_mb: "{{ (ansible_memtotal_mb * 0.20)|int|abs }}"
 zfs_arc_size_bytes: "{{ zfs_arc_size_mb }}000000"
 pwgen: "{{ lookup('password', '/dev/null chars=ascii_letters,digits,hexdigits,punctuation length=32') }}"
 common_pkgs:

roles/zfs/tasks/main.yml

@@ -47,22 +47,23 @@
       zfs
   register: zfsload
 
-# does not adjust to 75% of each host, depends on consistency between hosts - inconsistency leads to disproportionate allocations
-#- name: set zfs_arc_max to 75% installed memory ({{ zfs_arc_size_bytes }} bytes)
-#  lineinfile:
-#    path: "/etc/modprobe.d/zfs.conf"
-#    regexp: '^options zfs zfs_arc_max='
-#    line: 'options zfs zfs_arc_max="{{ zfs_arc_size_bytes }}"'
-#    create: yes
+# does not adjust to 20% of each host, depends on consistency between hosts - inconsistency leads to disproportionate allocations
+- name: set zfs_arc_max to 20% installed memory ({{ zfs_arc_size_bytes }} bytes)
+  lineinfile:
+    path: "/etc/modprobe.d/zfs.conf"
+    regexp: '^options zfs zfs_arc_max='
+    line: 'options zfs zfs_arc_max="{{ zfs_arc_size_bytes }}"'
+    create: yes
 
-- name: import pools
-  command: "zpool import -a"
+- name: check for data pool
+  command: "zpool list"
   register: pools
-  changed_when: "pools.stderr != 'no pools available to import'"
+  #ignore_errors: true
+  changed_when: pools.stdout.find('data') != -1
 
 - zpool_facts: properties='all'
 
 # really bad idempotence in here...
 - name: create zpool
   command: "zpool create -f -O compression=lz4 data {{ zfs_disk }} -o ashift=13 -O secondarycache=all"
-  when: ansible_zfs_pools is not defined
+  when: not pools.changed