checkpoint commit

active/software_btrfs/btrfs.md

@@ -1,6 +1,7 @@
 # BTRFS
 
 - [BTRFS](#btrfs)
+  - [Disk Usage](#disk-usage)
   - [Naming Conventions](#naming-conventions)
   - [Creating an Array](#creating-an-array)
   - [Converting an Array Between RAID Versions](#converting-an-array-between-raid-versions)
@@ -19,6 +20,15 @@ Oracle [has decent docs here](https://docs.oracle.com/en/operating-systems/oracl
 
 You'll also want to [read about btrfs compression](https://thelinuxcode.com/enable-btrfs-filesystem-compression/)
 
+## Disk Usage
+
+With compression, the actual size on disk can be obscured. Use the following
+command to check the actual file size of all files in a directory.
+
+```bash
+find . -name ".snapshots" -prune -o -type f -exec du -h {} + | sort -hr
+```
+
 ## Naming Conventions
 
 `poolX` is my naming convention for data pools. `pool0` is the first pool you create.