mgr/volume: default to 16 PGs (min) for metadata pool

Set the min so that the pg_autoscaler won't scale it back down.  Choose
something large enough that even for a large FS we'll do reasonably well
distributing the metadata workload across OSDs.

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit b567b110cb6286d4676653179cb86ae1fe861f15)

diff --git a/src/pybind/mgr/volumes/module.py b/src/pybind/mgr/volumes/module.py
index 4085fba7083c055bdc2b1d14f5d0ad7a7b558d28..c8a768c3164e7ecbd5d91f99bc62af6bc019b022 100644 (file)
--- a/src/pybind/mgr/volumes/module.py
+++ b/src/pybind/mgr/volumes/module.py
@@ -200,7 +200,8 @@ class Module(orchestrator.OrchestratorClientMixin, MgrModule):
         r, outb, outs = self.mon_command({
             'prefix': 'osd pool create',
             'pool': mdp_name,
-            'pg_num': 8
+            'pg_num': 16,
+            'pg_num_min': 16,
         })
         if r != 0:
             return r, outb, outs