Update README with additional disk preparation commands for Ceph

readme.md

@@ -97,7 +97,7 @@ For worker nodes:
 ```bash
 talosctl gen config \
         --output rendered/worker1.yaml                            \
-        --output-types controlplane                               \
+        --output-types worker                                     \
         --with-secrets secrets.yaml                               \
         --config-patch @nodes/worker1.yaml                        \
         --config-patch @patches/argocd.yaml                       \
@@ -189,11 +189,26 @@ kubectl run -it --rm \
     --overrides='{"spec": { "nodeSelector": {"kubernetes.io/hostname": "master3"}}}' fix
 ```
 
-Then run the following commands:
+Search for the correct disk with `blkid`, set `DISK=/dev/sdX`, then run (some of) the following commands:
 
 ```bash
 ceph-volume lvm zap /dev/sdX --destroy
 wipefs -a /dev/sdX
+# Zap the disk to a fresh, usable state (zap-all is important, b/c MBR has to be clean)
+sgdisk --zap-all $DISK
+
+# Wipe portions of the disk to remove more LVM metadata that may be present
+dd if=/dev/zero of="$DISK" bs=1K count=200 oflag=direct,dsync seek=0 # Clear at offset 0
+dd if=/dev/zero of="$DISK" bs=1K count=200 oflag=direct,dsync seek=$((1 * 1024**2)) # Clear at offset 1GB
+dd if=/dev/zero of="$DISK" bs=1K count=200 oflag=direct,dsync seek=$((10 * 1024**2)) # Clear at offset 10GB
+dd if=/dev/zero of="$DISK" bs=1K count=200 oflag=direct,dsync seek=$((100 * 1024**2)) # Clear at offset 100GB
+dd if=/dev/zero of="$DISK" bs=1K count=200 oflag=direct,dsync seek=$((1000 * 1024**2)) # Clear at offset 1000GB
+
+# SSDs may be better cleaned with blkdiscard instead of dd
+blkdiscard $DISK
+
+# Inform the OS of partition table changes
+partprobe $DISK
 ```
 
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