diff --git a/util/options.cc b/util/options.cc
index 7997aa969b4fe1dda7899270333393f2961c6450..c995877da0b7f75c02a89eccbc8078be6f0edcf3 100644
--- a/util/options.cc
+++ b/util/options.cc
@@ -91,7 +91,7 @@ Options::Options()
       purge_redundant_kvs_while_flush(true),
       allow_os_buffer(true),
       allow_mmap_reads(false),
-      allow_mmap_writes(true),
+      allow_mmap_writes(false),
       is_fd_close_on_exec(true),
       skip_log_error_on_recovery(false),
       stats_dump_period_sec(3600),
diff --git a/utilities/backupable/backupable_db_test.cc b/utilities/backupable/backupable_db_test.cc
index 62717f5dc14af237e221f4583a006bb091ccbe52..5a0b6928b8c4c92bf960865df3cf3cb5af3a4d8f 100644
--- a/utilities/backupable/backupable_db_test.cc
+++ b/utilities/backupable/backupable_db_test.cc
@@ -826,7 +826,7 @@ TEST(BackupableDBTest, RateLimiting) {
     auto rate_limited_backup_time = (bytes_written * kMicrosPerSec) /
                                     backupable_options_->backup_rate_limit;
     ASSERT_GT(backup_time, 0.9 * rate_limited_backup_time);
-    ASSERT_LT(backup_time, 1.3 * rate_limited_backup_time);
+    ASSERT_LT(backup_time, 1.5 * rate_limited_backup_time);
 
     CloseBackupableDB();
 
@@ -838,7 +838,7 @@ TEST(BackupableDBTest, RateLimiting) {
     auto rate_limited_restore_time = (bytes_written * kMicrosPerSec) /
                                      backupable_options_->restore_rate_limit;
     ASSERT_GT(restore_time, 0.9 * rate_limited_restore_time);
-    ASSERT_LT(restore_time, 1.3 * rate_limited_restore_time);
+    ASSERT_LT(restore_time, 1.5 * rate_limited_restore_time);
 
     AssertBackupConsistency(0, 0, 100000, 100010);
   }