diff --git a/src/mon/ConfigMap.cc b/src/mon/ConfigMap.cc
index 8b6f5e09070..b1228343bfd 100644
--- a/src/mon/ConfigMap.cc
+++ b/src/mon/ConfigMap.cc
@@ -37,14 +37,14 @@ void OptionMask::dump(Formatter *f) const
 
 void MaskedOption::dump(Formatter *f) const
 {
-  f->dump_string("name", opt.name);
+  f->dump_string("name", opt->name);
   f->dump_string("value", raw_value);
   mask.dump(f);
 }
 
 ostream& operator<<(ostream& out, const MaskedOption& o)
 {
-  out << o.opt.name;
+  out << o.opt->name;
   if (o.mask.location_type.size()) {
     out << "@" << o.mask.location_type << '=' << o.mask.location_value;
   }
@@ -114,7 +114,7 @@ void ConfigMap::generate_entity_map(
 	  continue;
 	}
       }
-      if (prev && prev->opt.name != i.first) {
+      if (prev && prev->opt->name != i.first) {
 	prev = nullptr;
       }
       if (prev &&
diff --git a/src/mon/ConfigMap.h b/src/mon/ConfigMap.h
index 86c25841962..7f6de46e198 100644
--- a/src/mon/ConfigMap.h
+++ b/src/mon/ConfigMap.h
@@ -51,11 +51,24 @@ struct OptionMask {
 };
 
 struct MaskedOption {
-  string raw_value;                          ///< raw, unparsed, unvalidated value
-  Option opt;                                ///< the option
+  string raw_value;               ///< raw, unparsed, unvalidated value
+  const Option *opt;              ///< the option
   OptionMask mask;
+  unique_ptr<const Option> unknown_opt; ///< if fabricated for an unknown option
 
-  MaskedOption(const Option& o) : opt(o) {}
+  MaskedOption(const Option *o, bool fab=false) : opt(o) {
+    if (fab) {
+      unknown_opt.reset(o);
+    }
+  }
+  MaskedOption(MaskedOption&& o) {
+    raw_value = std::move(o.raw_value);
+    opt = o.opt;
+    mask = std::move(o.mask);
+    unknown_opt = std::move(o.unknown_opt);
+  }
+  const MaskedOption& operator=(const MaskedOption& o) = delete;
+  const MaskedOption& operator=(MaskedOption&& o) = delete;
 
   /// return a precision metric (smaller is more precise)
   int get_precision(const CrushWrapper *crush);
diff --git a/src/mon/ConfigMonitor.cc b/src/mon/ConfigMonitor.cc
index 4f3b049d6c7..3b9dc704b48 100644
--- a/src/mon/ConfigMonitor.cc
+++ b/src/mon/ConfigMonitor.cc
@@ -151,7 +151,7 @@ bool ConfigMonitor::preprocess_command(MonOpRequestRef op)
       f->open_array_section("config");
     }
     for (auto s : sections) {
-      for (auto i : s.second->options) {
+      for (auto& i : s.second->options) {
 	if (!f) {
 	  tbl << s.first;
 	  tbl << i.second.mask.to_str();
@@ -389,11 +389,10 @@ void ConfigMonitor::load_config()
       who = key.substr(0, last_slash);
     }
 
-    Option fake_opt(name, Option::TYPE_STR, Option::LEVEL_DEV);
     const Option *opt = g_conf->find_option(name);
     if (!opt) {
       dout(10) << __func__ << " unrecognized option '" << name << "'" << dendl;
-      opt = &fake_opt;
+      opt = new Option(name, Option::TYPE_STR, Option::LEVEL_DEV);
     }
     string err;
     int r = opt->pre_validate(&value, &err);
@@ -403,7 +402,7 @@ void ConfigMonitor::load_config()
     }
 
     string section_name;
-    MaskedOption mopt(*opt);
+    MaskedOption mopt(opt);
     mopt.raw_value = value;
     if (who.size() &&
 	!ConfigMap::parse_mask(who, &section_name, &mopt.mask)) {
@@ -417,7 +416,7 @@ void ConfigMonitor::load_config()
 	  section = &config_map.by_type[section_name];
 	}
       }
-      section->options.insert(make_pair(name, mopt));
+      section->options.insert(make_pair(name, std::move(mopt)));
       ++num;
     }
     it->next();