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

AGENTS.md

@@ -76,17 +76,26 @@ tsys1=.1  tsys3=.3  tsys4=.4  tsys5=.5  tsys6=.6  tsys7=.7  tsys9=.9
 
 ## NFS export topology
 
-**tsys4 exports (primary, 68% of VMs depend on it):**
+**tsys4 exports (primary, overloaded):**
 - D2 = WDC Red 3TB HDD — most VMs live here
-- D3 = SK hynix 512GB SSD (USB-attached on tsys4)
 - D5 = Hitachi 2TB HDD
+- (sda Hitachi 1.8T at /mnt/albert — not NFS shared)
+- (sdd WDC 1T — idle, unmounted, removable)
+- (sdf WDC 4.5T SMR at /mnt/backup — PBS target)
 
-**tsys5 exports (secondary, barely used by k8s):**
+**tsys5 exports (fast-tier hub -- consolidated Friday):**
 - S1/S2/S3 = Seagate 1TB HDD each
 - S4 = Toshiba 500GB HDD
-- T5-SSD = Samsung 860 PRO 256GB SSD
+- T5-SSD = Samsung 860 PRO 256GB SSD (existing)
+- **D3 = SK hynix SC300 512GB SSD** (moving from tsys4 USB to tsys5 SAS Friday)
+- **NVMe (local, new Friday)** — local-only, wnode-tsys5 boot + HPC scratch
 
-**New Friday:** tsys5 NVMe (recommend local-only, not NFS-exported).
+**tsys5 hardware:** LSI SAS1068E (8-port, 5 free) + Intel ICH10 SATA (6-port,
+2 free) + 2x Renesas USB 3.0 xHCI. Plenty of room for the SSD + NVMe.
+
+**Friday change:** D3 export repoints from pfv-tsys4-nfs-stor to
+pfv-tsys5-nfs-stor. Update storage.cfg cluster-wide. VMs on D3 (currently
+none of significance — it's 99% empty) keep working after remount.
 
 ## SSH access