obsidian-yanxin/notes/Unraid Drive Replacement Plan.md

Unraid Drive Replacement Plan

Goals

• Reduce array from 8 to 5 HDD drives
• Replace consumer SMR drives with enterprise CMR
• Stay under 20% cumulative failure risk before each purchase
• Minimize cost and hassle

Current Array (as of 2026-03-28)

Slot	Model	Serial	Size	Age	Est. AFR	Health
Parity 1	ST8000DM004 SMR	ZCT2K65B	8TB	5.3yr	~4.5%	Had 180 GP errors (cleared)
Parity 2	ST8000DM004 SMR	ZCT2K5PQ	8TB	5.3yr	~3.5%	Had 19 GP errors (cleared)
Disk 1	ST8000DM004 SMR	ZCT2K3FF	8TB	5.3yr	~2.75%	Same manufacturing batch as parity drives
Disk 2	ST8000DM004 SMR	ZCT2K51K	8TB	5.3yr	~2.75%	1 CRC error, otherwise clean
Disk 3	ST8000DM004 SMR	ZCT3XAEJ	8TB	4.8yr	~3.5%	Had 10 GP errors, 2 CRC, 72K load cycles
Disk 4	WD40EFRX CMR	WD-WCC7K2YF4TDJ	4TB	6.6yr	~2.5%	Pristine SMART, only 1.7TB used
Disk 5	ST8000DM004 SMR	ZR14W632	8TB	2.5yr	~1.75%	56C lifetime max
Disk 6	ST8000DM004 SMR	ZR150CVS	8TB	2.5yr	~1.75%	Clean
Cache	Samsung 970 EVO	S5H9NS0N831296A	1TB	—	—	1% wear, excellent

• Combined monthly failure rate: ~1.9%
• Hits 20% cumulative failure at ~12 months (Mar 2027)
• Total data stored: ~25TB, growing ~1TB/year
• All 7 Seagate drives are consumer desktop SMR — not NAS-grade

Shopping List

#	Drive	Model	Purpose	Est. Price
1	Seagate Exos X18 16TB	ST16000NM000J	Parity 1	~$220
2	Seagate Exos X18 16TB	ST16000NM000J	Parity 2	~$220
3	Toshiba MG08 16TB	MG08ACA16TE	Data (Disk 1)	~$200
			Total	~$640

All are enterprise, CMR, 7200rpm, 5-year warranty.

Timeline

Phase 0 — Now (free)

Remove Disk 4 (WD Red 4TB)

Disk 4 only has 1.7TB used. Other drives have 14.5TB of free space. No purchase needed.

1. Open Unbalance plugin
2. Source: Disk 4
3. Destination: Disk 3, Disk 5, Disk 6 (most free space)
4. Start transfer (~30 min for 1.7TB)
5. Verify Disk 4 is empty
6. Stop array (Main → Stop)
7. Unassign Disk 4 (click on the drive slot → set to "No Device")
8. Start array → confirm new configuration
9. Parity sync will run (~12-18 hrs, array is usable during sync)
10. Power down, physically remove the 4TB drive, power up

Result: 8 → 7 drives. Keep the WD Red as a cold spare — it has pristine SMART.

---

Phase 1 — April 2027

Buy: 1x Seagate Exos X18 16TB (~$220) Replace: Parity 1 (ZCT2K65B — worst drive, had 180 GP errors) Remove: Disk 3 (ZCT3XAEJ — next worst, had 10 GP errors + 2 CRC + 72K load cycles)

Cumulative failure risk at this point: ~20%

Step 1: Replace Parity 1

1. Stop array
2. Power down server
3. Remove old Parity 1 drive (sdb, serial ZCT2K65B)
4. Install new Exos X18 16TB in the same slot
5. Power up → Main page → verify new drive shows in Parity 1 slot
6. Start array → Parity sync begins (~12-18 hrs)
7. Array is fully usable during sync — avoid heavy writes
8. Wait for sync to complete (check Main page for progress)

Step 2: Remove Disk 3

9. Open Unbalance plugin
10. Source: Disk 3 (~4.3TB)
11. Destination: Disk 1, Disk 2, Disk 5, Disk 6
12. Start transfer (~2-4 hrs)
13. Verify Disk 3 is empty
14. Stop array
15. Unassign Disk 3
16. Start array → confirm new configuration → parity sync (~12-18 hrs)
17. Power down, physically remove old Disk 3, power up

Disposal

• Old Parity 1 (ZCT2K65B): Recycle — worst error history
• Old Disk 3 (ZCT3XAEJ): Recycle — 2nd worst

Result: 7 → 6 drives.

---

Phase 2 — June 2027

Buy: 1x Seagate Exos X18 16TB (~$220) Replace: Parity 2 (ZCT2K5PQ — had 19 GP errors)

Steps

1. Stop array
2. Power down, swap Parity 2 with new Exos X18 16TB
3. Power up → verify drive assignment → Start array
4. Parity sync (~12-18 hrs)

Disposal

• Old Parity 2 (ZCT2K5PQ): Recycle

Result: Still 6 drives. Cannot remove another drive yet — remaining 8TB data drives are too full to consolidate without a 16TB data drive.

---

Phase 3 — October 2027

Buy: 1x Toshiba MG08 16TB (~$200) Replace: Disk 1 (ZCT2K3FF — same batch as old parity, 5.3yr old) Remove: Disk 5 (ZR14W632 — had temperature issues)

Step 1: Replace Disk 1

1. Stop array
2. Power down, swap Disk 1 with new Toshiba MG08 16TB
3. Power up → verify drive assignment → Start array
4. Rebuild begins (~18-20 hrs) — reconstructs Disk 1's data from parity
5. Array is usable during rebuild

Step 2: Remove Disk 5

6. Open Unbalance plugin
7. Source: Disk 5 (~5.2TB)
8. Destination: Disk 1 (new 16TB, ~9.4TB free after rebuild)
9. Start transfer (~3-5 hrs)
10. Verify Disk 5 is empty
11. Stop array
12. Unassign Disk 5
13. Start array → confirm → parity sync (~12-18 hrs)
14. Power down, physically remove old Disk 5, power up

Disposal

• Old Disk 1 (ZCT2K3FF): Recycle — same batch as failed parity drives
• Old Disk 5 (ZR14W632): Keep as emergency spare — only 2.5yr old, clean SMART

Result: 6 → 5 drives. Migration complete.

---

Final Array (October 2027)

Slot	Drive	Size	Used	Source	Brand
Parity 1	Exos X18	16TB	—	New (Apr 2027)	Seagate
Parity 2	Exos X18	16TB	—	New (Jun 2027)	Seagate
Disk 1	MG08	16TB	~12TB	New (Oct 2027)	Toshiba
Disk 2	ST8000DM004	8TB	~6.3TB	Original	Seagate
Disk 6	ST8000DM004	8TB	~5.2TB	Original	Seagate

• Usable capacity: 30.6TB (16 + 7.3 + 7.3)
• Data stored: ~25TB with ~6TB free
• Growth runway: ~6 years at 1TB/year
• Annual failure rate: ~4% (down from ~19%)
• 3 empty drive bays for future expansion

Optional Future Upgrade

When Disk 2 (5.3yr) or Disk 6 (2.5yr) eventually show wear, or if you want more space:

Replace	With	Cost	New usable
Disk 2 → 16TB enterprise	Toshiba or WD	~$200-230	38.6TB
Disk 6 → 16TB enterprise	Toshiba or WD	~$200-230	48TB

Going all-enterprise (5x 16TB) costs an additional ~$430 and gives 48TB usable (23+ years of growth). No rush — Disk 6 especially is young and healthy.

If a Drive Fails Before Scheduled Replacement

Parity drive fails:

• Buy the replacement Exos X18 16TB
• Swap, parity sync, done
• Other parity still protects the array during sync

Data drive fails (8TB):

• Array keeps running — data is emulated from parity in real-time
• Buy a 16TB replacement (must upgrade parity first if no parity is ≥16TB yet)
• Swap, rebuild, done

Data drive fails (new 16TB):

• Same process, buy another 16TB
• Dual parity protects against up to 2 simultaneous failures

Drives to Keep After Migration

Drive	Reason
WD Red 4TB (WD-WCC7K2YF4TDJ)	Cold spare — pristine SMART despite 6.6yr age
Disk 5 8TB (ZR14W632)	Emergency spare — only 2.5yr old

Drives to Recycle

Drive	Reason
Parity 1 (ZCT2K65B)	180 GP error history
Parity 2 (ZCT2K5PQ)	19 GP error history
Disk 3 (ZCT3XAEJ)	10 GP errors + 2 CRC + 72K load cycles
Disk 1 (ZCT2K3FF)	Same batch as parity drives, 5.3yr

Pending Config Fixes

These can be done anytime from the Unraid WebGUI — no downtime needed:

• Remove compose.manager plugin (Settings → Plugins → click X)
• Set disk share security to Private (Settings → Global Share Settings → Disk Shares → No)
• Set user share security to Private (Shares → each share → SMB Security → Private)
• Move domains share to cache (Shares → domains → Use Cache → Prefer, Cache Pool → cache)
• Set up email notifications (Settings → Notification Settings)
• Configure UPS auto-shutdown (Settings → UPS Settings — CyberPower CP1500 via USB, nut-dw plugin installed)
• Enable XMP in BIOS at next reboot (RAM: G.Skill DDR3 1600MHz running at 1333MHz)
• Verify appdata backups — test a restore

SMART Test Schedule (already configured)

• Weekly short: Sundays 2:00 AM (0 2 * * 0)
• Monthly extended: 1st of month 3:00 AM (0 3 1 * *)
• Configured via User Scripts plugin