SERVER-17861 Change the default storage engine to wiredTiger.

WiredTiger is used as the default storage engine if the dbpath does
not contain any data files. Otherwise, the storage engine specified
in the storage.bson metadata file is used when the --storageEngine
flag is omitted from the command line invocation.

1 files changed, 5 insertions, 3 deletions

diff --git a/src/mongo/db/mongod_options.cpp b/src/mongo/db/mongod_options.cpp
index bb283121bf3..a2daab9c201 100644
--- a/src/mongo/db/mongod_options.cpp
+++ b/src/mongo/db/mongod_options.cpp
@@ -165,8 +165,7 @@ namespace mongo {
         // Storage Options
 
         storage_options.addOptionChaining("storage.engine", "storageEngine", moe::String,
-                                          "what storage engine to use")
-            .setDefault(moe::Value(std::string("mmapv1")));
+                "what storage engine to use - defaults to wiredTiger if no data files present");
 
 
 #ifdef _WIN32
@@ -894,7 +893,10 @@ namespace mongo {
                           "files");
         }
 
-        storageGlobalParams.engine = params["storage.engine"].as<string>();
+        if (params.count("storage.engine")) {
+            storageGlobalParams.engine = params["storage.engine"].as<string>();
+            storageGlobalParams.engineSetByUser = true;
+        }
 
         if (params.count("storage.dbPath")) {
             storageGlobalParams.dbpath = params["storage.dbPath"].as<string>();