Adds configurable osd-journal-size option

Fixes: bug 1259919

config.yaml

@@ -17,6 +17,17 @@ options:
       no journal device will be used.
       .
       Only supported with ceph >= 0.48.3.
+  osd-journal-size:
+    type: int
+    default: 1024
+    description: |
+      Ceph osd journal size. The journal size should be at least twice the
+      product of the expected drive speed multiplied by filestore max sync
+      interval. However, the most common practice is to partition the journal
+      drive (often an SSD), and mount it such that Ceph uses the entire
+      partition for the journal.
+      .
+      Only supported with ceph >= 0.48.3.
   osd-format:
     type: string
     default: xfs

hooks/hooks.py

@@ -70,7 +70,8 @@ def emit_cephconf():
         'auth_supported': get_auth(),
         'mon_hosts': ' '.join(mon_hosts),
         'fsid': get_fsid(),
-        'version': ceph.get_ceph_version()
+        'version': ceph.get_ceph_version(),
+        'osd_journal_size': config('osd-journal-size')
     }
     # Install ceph.conf as an alternative to support
     # co-existence with other charms that write this file

revision

@@ -1 +1 @@
-13
+14

templates/ceph.conf

@@ -18,6 +18,6 @@
 
 [osd]
  keyring = /var/lib/ceph/osd/$cluster-$id/keyring
- osd journal size = 1000
+ osd journal size = {{ osd_journal_size }}
  filestore xattr use omap = true