Add a note for the disk removal rejection

docs/host/host.md

@@ -272,6 +272,12 @@ The replica data would be rebuilt to another disk automatically to keep the high
 
 :::
 
+:::note
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+If the disc contains last healthy replica of volume or backing image, disk removal is rejected. In case a single replica of those objects is configured, move the replica to another disk or remove the objects altogether to acknowledge that you don't need them. In case there is a replication fault, fix the faulty replicas on the other disks before proceeding with the deletion of the current one.
+
+:::
+
 #### Identify the disk to remove (Harvester dashboard)
 1. Go to the **Hosts** page.
 2. On the node containing the disk, select the node name and go to the **Storage** tab.