diff --git a/how-to/what-is-vm-cache-and-how-do-I-use-it.md b/how-to/what-is-vm-cache-and-how-do-I-use-it.md
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@@ -0,0 +1,45 @@
+# What Is VMCache and How To Enable It
+
+* [What is VMCache](#what-is-vmcache-and-how-to-enable-it)
+* [How is this different to VM templating](#how-is-this-different-to-vm-templating)
+* [How to enable VMCache](#how-to-enable-vmcache)
+* [Limitations](#limitations)
+
+### What is VMCache
+VMCache is a new function that creates VMs as caches before using it.
+It helps speed up new container creation.  
+The function consists of a server and some clients communicating
+through Unix socket.  The protocol is gRPC in [protocols/cache/cache.proto](https://github.com/kata-containers/runtime/blob/master/protocols/cache/cache.proto).  
+The VMCache server will create some VMs and cache them by factory cache.
+It will convert the VM to gRPC format and transport it when gets
+requested from clients.  
+Factory grpccache is the VMCache client.  It will request gRPC format
+VM and convert it back to a VM.  If VMCache function is enabled,
+kata-runtime will request VM from factory grpccache when it creates
+a new sandbox.
+
+### How is this different from VM templating
+Both [VM templating](https://github.com/kata-containers/documentation/blob/master/how-to/what-is-vm-templating-and-how-do-I-use-it.md) and VMCache help speed up new container creation.  
+When VM templating enabled, new VMs are created by cloning from a pre-created template VM, and they will share the same initramfs, kernel and agent memory in readonly mode.  So it saves a lot of memory if there are many Kata Containers running on the same host.  
+VMCache is not vulnerable to [share memory CVE](https://github.com/kata-containers/documentation/blob/master/how-to/what-is-vm-templating-and-how-do-I-use-it.md#what-are-the-cons) because each VM doesn't share the memory.
+
+### How to enable VMCache
+VMCache can be enabled by changing your Kata Containers config file (`/usr/share/defaults/kata-containers/configuration.toml`,
+overridden by `/etc/kata-containers/configuration.toml` if provided) such that:
+* `vm_cache_number` specifies the number of caches of VMCache:
+    *  unspecified or == 0  
+       VMCache is disabled
+    * `> 0`  
+      will be set to the specified number
+*  `vm_cache_endpoint` specifies the address of the Unix socket.
+
+Then you can create a VM templating for later usage by calling:
+```
+$ sudo kata-runtime factory init
+```
+and purge it by ctrl-c it.
+
+### Limitations
+* Cannot work with VM templating.
+* Cannot work with vsock.
+* Only supports the qemu hypervisor.
diff --git a/how-to/what-is-vm-templating-and-how-do-I-use-it.md b/how-to/what-is-vm-templating-and-how-do-I-use-it.md
index 423aeaaa8c..1d2974a415 100644
--- a/how-to/what-is-vm-templating-and-how-do-I-use-it.md
+++ b/how-to/what-is-vm-templating-and-how-do-I-use-it.md
@@ -7,6 +7,11 @@ by cloning from a pre-created template VM, and they will share the
 same initramfs, kernel and agent memory in readonly mode. It is very
 much like a process fork done by the kernel but here we *fork* VMs.
 
+### How is this different from VMCache
+Both [VMCache](https://github.com/kata-containers/documentation/blob/master/how-to/what-is-vm-cache-and-how-do-I-use-it.md) and VM templating help speed up new container creation.  
+When VMCache enabled, new VMs are created by the VMCache server.  So it is not vulnerable to share memory CVE because each VM doesn't share the memory.  
+VM templating saves a lot of memory if there are many Kata Containers running on the same host.
+
 ### What are the Pros
 VM templating helps speed up new container creation and saves a lot
 of memory if there are many Kata Containers running on the same host.