add notes for resizing a qemu images

active/software_qemu/qemu.md

@@ -7,6 +7,7 @@
     - [Convert bootable drive to qcow](#convert-bootable-drive-to-qcow)
   - [ISO](#iso)
   - [ISO Access Denied on Boot](#iso-access-denied-on-boot)
+  - [Resize an image](#resize-an-image)
 
 ## QCOW2
 
@@ -57,3 +58,14 @@ mkisofs -r -iso-level 4 -l -o /tmp/arch-files.iso ./arch
 ## ISO Access Denied on Boot
 
 Turn off Secure Boot in the VM. Bios -> Device Manager -> Secure Boot Configuration -> Uncheck Attempt Secure Boot
+
+## Resize an image
+
+```bash
+# Add more disk space
+qemu-img resize <my_vm>.raw +10G
+
+# Grow the partition and filesystem. For ext4:
+growpart /dev/vda 1
+resize2fs /dev/vda1
+```