Section 4. Under the hood

notes/4_under_the_hood.md

@@ -96,3 +96,35 @@ Set limit for
 * Scheduling CPU time
 * Memory allocation limits
 * Inherited limitations and quotas (summed total cannot exceed the limit)
+
+## Storage
+
+Discuss how container storage work
+
+### Unix Storage in Brief
+* Actual storage devices are binary info on hardware, managed by kernel
+* Logical storage devices (logical groups, like partition drive into different parts)
+* Filesystems
+* FUSE filesystems and network filesystems
+
+### The Secret of Dockers: COWs
+
+Copy on Write layer: Container see the combined result of real file and a its own file system layer. When writing to file, instead of directly write on file, we write on the file system layer
+
+???? Need more understanding
+
+### Moving Cows
+
+* The contents of layers are moved between containers in gzip files
+* Containers are independent of the storage engine
+* Any container can be loaded (almost) everywhere
+* It's possible to run out of layers on some of the storage engines
+
+### Volumes and Bind Mounting
+
+* The Linux VFS (Virtual File System)
+* Mounting devices on the VFS
+
+????
+
+TODO: relearn these content (networking, process, storage of docker, etc)