diff --git a/src/common/config_opts.h b/src/common/config_opts.h
index a0e6ad7353d..cdf2d56c8ca 100644
--- a/src/common/config_opts.h
+++ b/src/common/config_opts.h
@@ -762,7 +762,7 @@ OPTION(keyvaluestore_rocksdb_options, OPT_STR, "")
 // rocksdb options that will be used for omap(if omap_backend is rocksdb)
 OPTION(filestore_rocksdb_options, OPT_STR, "")
 // rocksdb options that will be used in monstore
-OPTION(mon_rocksdb_options, OPT_STR, "")
+OPTION(mon_rocksdb_options, OPT_STR, "cache_size=536870912,write_buffer_size=33554432,block_size=65536,compression=kNoCompression")
 
 /**
  * osd_*_priority adjust the relative priority of client io, recovery io,
@@ -814,7 +814,7 @@ OPTION(memstore_page_size, OPT_U64, 64 << 10)
 OPTION(newstore_max_dir_size, OPT_U32, 1000000)
 OPTION(newstore_onode_map_size, OPT_U32, 1024)   // onodes per collection
 OPTION(newstore_backend, OPT_STR, "rocksdb")
-OPTION(newstore_backend_options, OPT_STR, "")
+OPTION(newstore_rocksdb_options, OPT_STR, "compression=kNoCompression,max_write_buffer_number=16,min_write_buffer_number_to_merge=6")
 OPTION(newstore_fail_eio, OPT_BOOL, true)
 OPTION(newstore_sync_io, OPT_BOOL, false)  // perform initial io synchronously
 OPTION(newstore_sync_transaction, OPT_BOOL, false)  // perform kv txn synchronously
@@ -836,7 +836,6 @@ OPTION(newstore_overlay_max_length, OPT_INT, 65536)
 OPTION(newstore_overlay_max, OPT_INT, 32)
 OPTION(newstore_open_by_handle, OPT_BOOL, true)
 OPTION(newstore_o_direct, OPT_BOOL, true)
-OPTION(newstore_db_path, OPT_STR, "")
 OPTION(newstore_aio, OPT_BOOL, true)
 OPTION(newstore_aio_poll_ms, OPT_INT, 250)  // milliseconds
 OPTION(newstore_aio_max_queue_depth, OPT_INT, 4096)
diff --git a/src/kv/RocksDBStore.cc b/src/kv/RocksDBStore.cc
index 6dfde87a890..a6d071e48aa 100644
--- a/src/kv/RocksDBStore.cc
+++ b/src/kv/RocksDBStore.cc
@@ -6,6 +6,9 @@
 #include <string>
 #include <memory>
 #include <errno.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
 
 #include "rocksdb/db.h"
 #include "rocksdb/table.h"
@@ -107,6 +110,26 @@ int RocksDBStore::init(string _options_str)
   return 0;
 }
 
+int RocksDBStore::create_and_open(ostream &out)
+{
+  // create tertiary paths
+  string wal_path = path + ".wal";
+  struct stat st;
+  int r = ::stat(wal_path.c_str(), &st);
+  if (r < 0)
+    r = -errno;
+  if (r == -ENOENT) {
+    unsigned slashoff = path.rfind('/');
+    string target = path.substr(slashoff + 1);
+    r = ::symlink(target.c_str(), wal_path.c_str());
+    if (r < 0) {
+      out << "failed to symlink " << wal_path << " to " << target;
+      return -errno;
+    }
+  }
+  return do_open(out, true);
+}
+
 int RocksDBStore::do_open(ostream &out, bool create_if_missing)
 {
   rocksdb::Options opt;
@@ -117,6 +140,7 @@ int RocksDBStore::do_open(ostream &out, bool create_if_missing)
     return -EINVAL;
   }
   opt.create_if_missing = create_if_missing;
+  opt.wal_dir = path + ".wal";
 
   status = rocksdb::DB::Open(opt, path, &db);
   if (!status.ok()) {
diff --git a/src/kv/RocksDBStore.h b/src/kv/RocksDBStore.h
index 257bb2d1c24..90523c451b7 100644
--- a/src/kv/RocksDBStore.h
+++ b/src/kv/RocksDBStore.h
@@ -124,9 +124,7 @@ public:
     return do_open(out, false);
   }
   /// Creates underlying db if missing and opens it
-  int create_and_open(ostream &out) {
-    return do_open(out, true);
-  }
+  int create_and_open(ostream &out);
 
   void close();
 
diff --git a/src/os/fs/FS.cc b/src/os/fs/FS.cc
index cb0bdd53a13..b7c7987997c 100644
--- a/src/os/fs/FS.cc
+++ b/src/os/fs/FS.cc
@@ -121,16 +121,49 @@ int FS::zero(int fd, uint64_t offset, uint64_t length)
 {
   int r;
 
-#ifdef CEPH_HAVE_FALLOCATE
-# if !defined(DARWIN) && !defined(__FreeBSD__)
+  /*
+
+    From the fallocate(2) man page:
+
+       Specifying the FALLOC_FL_PUNCH_HOLE flag (available since Linux 2.6.38)
+       in mode deallocates space (i.e., creates a  hole)  in  the  byte  range
+       starting  at offset and continuing for len bytes.  Within the specified
+       range, partial filesystem  blocks  are  zeroed,  and  whole  filesystem
+       blocks  are removed from the file.  After a successful call, subsequent
+       reads from this range will return zeroes.
+
+       The FALLOC_FL_PUNCH_HOLE flag must be ORed with FALLOC_FL_KEEP_SIZE  in
+       mode;  in  other words, even when punching off the end of the file, the
+       file size (as reported by stat(2)) does not change.
+
+       Not all  filesystems  support  FALLOC_FL_PUNCH_HOLE;  if  a  filesystem
+       doesn't  support the operation, an error is returned.  The operation is
+       supported on at least the following filesystems:
+
+       *  XFS (since Linux 2.6.38)
+
+       *  ext4 (since Linux 3.0)
+
+       *  Btrfs (since Linux 3.7)
+
+       *  tmpfs (since Linux 3.5)
+
+   So: we only do this is PUNCH_HOLE *and* KEEP_SIZE are defined.
+
+  */
+#if !defined(DARWIN) && !defined(__FreeBSD__)
+# ifdef CEPH_HAVE_FALLOCATE
+#  ifdef FALLOC_FL_KEEP_SIZE
   // first try fallocate
-  r = fallocate(fd, FALLOC_FL_PUNCH_HOLE, offset, length);
+  r = fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, offset, length);
   if (r < 0) {
     r = -errno;
   }
   if (r != -EOPNOTSUPP) {
     goto out;  // a real error
   }
+  // if that failed (-EOPNOTSUPP), fall back to writing zeros.
+#  endif
 # endif
 #endif
 
@@ -140,7 +173,7 @@ int FS::zero(int fd, uint64_t offset, uint64_t length)
     bufferptr bp(length);
     bp.zero();
     bl.append(bp);
-    int r = ::lseek64(fd, offset, SEEK_SET);
+    r = ::lseek64(fd, offset, SEEK_SET);
     if (r < 0) {
       r = -errno;
       goto out;
diff --git a/src/os/newstore/NewStore.cc b/src/os/newstore/NewStore.cc
index bb69babc235..e1b4d73ae16 100644
--- a/src/os/newstore/NewStore.cc
+++ b/src/os/newstore/NewStore.cc
@@ -564,7 +564,6 @@ NewStore::NewStore(CephContext *cct, const string& path)
     cct(cct),
     db(NULL),
     fs(NULL),
-    db_path(cct->_conf->newstore_db_path),
     path_fd(-1),
     fsid_fd(-1),
     frag_fd(-1),
@@ -803,7 +802,7 @@ bool NewStore::test_mount_in_use()
   return ret;
 }
 
-int NewStore::_open_db()
+int NewStore::_open_db(bool create)
 {
   assert(!db);
   char fn[PATH_MAX];
@@ -817,17 +816,24 @@ int NewStore::_open_db()
     db = NULL;
     return -EIO;
   }
-  db->init(g_conf->newstore_backend_options);
+  string options;
+  if (g_conf->newstore_backend == "rocksdb")
+    options = g_conf->newstore_rocksdb_options;
+  db->init(options);
   stringstream err;
-  if (db->create_and_open(err)) {
+  int r;
+  if (create)
+    r = db->create_and_open(err);
+  else
+    r = db->open(err);
+  if (r) {
     derr << __func__ << " erroring opening db: " << err.str() << dendl;
     delete db;
     db = NULL;
     return -EIO;
   }
   dout(1) << __func__ << " opened " << g_conf->newstore_backend
-	  << " path " << path
-	  << " options " << g_conf->newstore_backend_options << dendl;
+	  << " path " << path << " options " << options << dendl;
   return 0;
 }
 
@@ -927,12 +933,7 @@ int NewStore::mkfs()
   if (r < 0)
     goto out_close_fsid;
 
-  if (db_path != "") {
-    r = symlinkat(db_path.c_str(), path_fd, "db");
-    if (r < 0)
-      goto out_close_frag;
-  }
-  r = _open_db();
+  r = _open_db(true);
   if (r < 0)
     goto out_close_frag;
 
@@ -976,7 +977,7 @@ int NewStore::mount()
 
   // FIXME: superblock, features
 
-  r = _open_db();
+  r = _open_db(false);
   if (r < 0)
     goto out_frag;
 
diff --git a/src/os/newstore/NewStore.h b/src/os/newstore/NewStore.h
index 0e3b39350ef..c32e2a9d45e 100644
--- a/src/os/newstore/NewStore.h
+++ b/src/os/newstore/NewStore.h
@@ -461,7 +461,6 @@ private:
   KeyValueDB *db;
   FS *fs;
   uuid_d fsid;
-  string db_path;
   int path_fd;  ///< open handle to $path
   int fsid_fd;  ///< open handle (locked) to $path/fsid
   int frag_fd;  ///< open handle to $path/fragments
@@ -525,7 +524,7 @@ private:
   int _open_frag();
   int _create_frag();
   void _close_frag();
-  int _open_db();
+  int _open_db(bool create);
   void _close_db();
   int _open_collections();
   void _close_collections();