feat: relocate D3 SSD from tsys4 USB to tsys5 SAS on Friday

Deep-dive on tsys4/5 storage controllers revealed:
- tsys4: 4-port SATA, all occupied; D3 SSD is USB 2.0
- tsys5: LSI SAS1068E (8-port, 5 free) + ICH10 SATA (2 free) + USB 3.0

Decision: move D3 (SK hynix SSD) to a tsys5 SAS port. Eliminates USB
bottleneck and consolidates all fast storage on tsys5: NVMe (local) +
D3 SSD + T5-SSD + 4 HDD exports.

Updated storage architecture, speed tiers, critical VM placement,
failure survival matrix, StorageClass design, and Friday plan.

💘 Generated with Crush

Assisted-by: Crush:glm-5.2

TODO.md

@@ -138,7 +138,7 @@ wmic path win32_videocontroller get name,adapterram,driverversion
 5. Reboot to activate new NIC and NFS nconnect.
 6. Run `validate-fixes.sh pfv-tsys4` to confirm.
 
-### tsys5 — plug storage cable + install NVMe
+### tsys5 — plug storage cable + install NVMe + relocate D3 SSD
 
 1. Plug the **second ethernet cable** into tsys5's dedicated storage NIC.
 2. Verify bond0 recovery: `cat /proc/net/bonding/bond0` — look for
@@ -147,10 +147,19 @@ wmic path win32_videocontroller get name,adapterram,driverversion
    ```bash
    echo "layer3+4" > /sys/class/net/bond0/bonding/xmit_hash_policy
    ```
-4. Install the **PCI NVMe drive**.
-5. Format NVMe as local directory storage (see TODO section 3 below).
-6. Reboot tsys5 to activate NFS nconnect.
-7. Run `validate-fixes.sh pfv-tsys5` to confirm.
+4. **Relocate D3 SSD** from tsys4 USB to tsys5 SAS port:
+   - Power down tsys4
+   - Remove the SK hynix SC300 SSD from its USB enclosure on tsys4
+   - Install it on a free SAS port on tsys5 (5 ports free on LSI SAS1068E)
+   - On tsys5: mount as `/mnt/pfv-tsys5/D3`, add to `/etc/exports`
+   - Update `/etc/pve/storage.cfg` cluster-wide: repoint D3 `server` from
+     `pfv-tsys4-nfs-stor` to `pfv-tsys5-nfs-stor`, update `export` path
+   - Copy any existing D3 data from tsys4 first (currently ~2 MB, essentially
+     empty, so minimal migration)
+5. Install the **PCI NVMe drive** (uses a PCI slot, not a SATA/SAS port).
+6. Format NVMe as local directory storage (see TODO section 3 below).
+7. Reboot tsys5 to activate NFS nconnect.
+8. Run `validate-fixes.sh pfv-tsys5` to confirm.
 
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