diff --git a/vmm/src/api/openapi/cloud-hypervisor.yaml b/vmm/src/api/openapi/cloud-hypervisor.yaml
index d00873f56..b23bfff63 100644
--- a/vmm/src/api/openapi/cloud-hypervisor.yaml
+++ b/vmm/src/api/openapi/cloud-hypervisor.yaml
@@ -324,6 +324,9 @@ components:
         queue_size:
           type: integer
           default: 1024
+        dax:
+          type: boolean
+          default: true
         cache_size:
           type: integer
           format: int64
diff --git a/vmm/src/config.rs b/vmm/src/config.rs
index eeba43102..5eb58d20f 100644
--- a/vmm/src/config.rs
+++ b/vmm/src/config.rs
@@ -436,8 +436,10 @@ pub struct FsConfig {
     pub num_queues: usize,
     #[serde(default = "default_fsconfig_queue_size")]
     pub queue_size: u16,
+    #[serde(default = "default_fsconfig_dax")]
+    pub dax: bool,
     #[serde(default = "default_fsconfig_cache_size")]
-    pub cache_size: Option<u64>,
+    pub cache_size: u64,
 }
 
 fn default_fsconfig_num_queues() -> usize {
@@ -448,8 +450,12 @@ fn default_fsconfig_queue_size() -> u16 {
     1024
 }
 
-fn default_fsconfig_cache_size() -> Option<u64> {
-    Some(0x0002_0000_0000)
+fn default_fsconfig_dax() -> bool {
+    true
+}
+
+fn default_fsconfig_cache_size() -> u64 {
+    0x0002_0000_0000
 }
 
 impl FsConfig {
@@ -482,9 +488,9 @@ impl FsConfig {
 
         let mut num_queues: usize = default_fsconfig_num_queues();
         let mut queue_size: u16 = default_fsconfig_queue_size();
-        let mut dax: bool = true;
+        let mut dax: bool = default_fsconfig_dax();
         // Default cache size set to 8Gib.
-        let mut cache_size: Option<u64> = default_fsconfig_cache_size();
+        let mut cache_size: u64 = default_fsconfig_cache_size();
 
         if tag.is_empty() {
             return Err(Error::ParseFsTagParam);
@@ -516,9 +522,9 @@ impl FsConfig {
             if !cache_size_str.is_empty() {
                 return Err(Error::InvalidCacheSizeWithDaxOff);
             }
-            cache_size = None;
+            cache_size = 0;
         } else if !cache_size_str.is_empty() {
-            cache_size = Some(parse_size(cache_size_str)?);
+            cache_size = parse_size(cache_size_str)?;
         }
 
         Ok(FsConfig {
@@ -526,6 +532,7 @@ impl FsConfig {
             sock: PathBuf::from(sock),
             num_queues,
             queue_size,
+            dax,
             cache_size,
         })
     }
diff --git a/vmm/src/device_manager.rs b/vmm/src/device_manager.rs
index 077509188..22309b6f5 100644
--- a/vmm/src/device_manager.rs
+++ b/vmm/src/device_manager.rs
@@ -977,8 +977,8 @@ impl DeviceManager {
         if let Some(fs_list_cfg) = &vm_info.vm_cfg.lock().unwrap().fs {
             for fs_cfg in fs_list_cfg.iter() {
                 if let Some(fs_sock) = fs_cfg.sock.to_str() {
-                    let mut cache: Option<(VirtioSharedMemoryList, u64)> = None;
-                    if let Some(fs_cache) = fs_cfg.cache_size {
+                    let cache: Option<(VirtioSharedMemoryList, u64)> = if fs_cfg.dax {
+                        let fs_cache = fs_cfg.cache_size;
                         // The memory needs to be 2MiB aligned in order to support
                         // hugepages.
                         let fs_guest_addr = allocator
@@ -1023,15 +1023,18 @@ impl DeviceManager {
                             offset: 0,
                             len: fs_cache,
                         });
-                        cache = Some((
+
+                        Some((
                             VirtioSharedMemoryList {
                                 addr: fs_guest_addr,
                                 len: fs_cache as GuestUsize,
                                 region_list,
                             },
                             addr as u64,
-                        ));
-                    }
+                        ))
+                    } else {
+                        None
+                    };
 
                     let virtio_fs_device = vm_virtio::vhost_user::Fs::new(
                         fs_sock,