docs: EMC shelf LCC types & fan control (Viper vs Derringer) #64

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2026-09-05 21:02:40 +00:00

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Records the EMC shelf finding from the 2026-09-05 investigation into quieting the shelf that holds the Nimble scrap SSDs.

What was found (live, via `sg_ses`)

Viper LCC — EMC KTN-STL3, 15-bay 3.5", chassis 046-002-858-A03 (both of Aegis's 3.5" shelves). Handles SATA via STP, self-idles fans quiet (~2600 rpm), honors sg_ses speed_code control. The good one.
Derringer LCC — EMC 25-bay 2.5" SAE (VNXB6GSDAE25). Trialled then rejected for the SATA SSDs:
- The LCC that sees the SATA drives locks its fans at 10230 rpm and ignores every speed_code write.
- The peer LCC honors fan control (floor ~6350 rpm) but cannot see SATA drives at all — drive-bay phys never link, even after a cold power-cycle with the peer unseated — and holds a permanent CRIT=1 plus mpt3sas log_info(0x31120434) phy-retry spam.
- Dual-cabling both LCCs gets quiet fans + visible drives but keeps the cosmetic CRIT.
- Use the SAE only with SAS (dual-port) drives.
speed_code clamps its effective minimum at 3 on both families; --index=coo,N resolves to an empty descriptor on these LCCs (use 20,0 etc.).

Changes

docs/homelab-architecture.md — new "EMC disk shelves (Aegis external SAS) — LCC types & fan control" subsection under Key learnings.
unraid-sas-shelf-bench/CLAUDE.md — short cross-reference pointer.

Docs only. The SSDs now live on the second Viper/KTN shelf (adapted for 2.5"), quiet and fault-free.

🤖 Generated with Claude Code

https://claude.ai/code/session_01AzjHJ1DX36rdxK5HhKKjnE

Records the EMC shelf finding from the 2026-09-05 investigation into quieting the shelf that holds the Nimble scrap SSDs. ## What was found (live, via `sg_ses`) - **Viper LCC** — EMC KTN-STL3, 15-bay 3.5", chassis `046-002-858-A03` (both of Aegis's 3.5" shelves). Handles SATA via STP, self-idles fans quiet (~2600 rpm), honors `sg_ses` `speed_code` control. The good one. - **Derringer LCC** — EMC 25-bay 2.5" SAE (`VNXB6GSDAE25`). Trialled then rejected for the SATA SSDs: - The LCC that sees the SATA drives **locks its fans at 10230 rpm** and ignores every `speed_code` write. - The peer LCC honors fan control (floor ~6350 rpm) but **cannot see SATA drives at all** — drive-bay phys never link, even after a cold power-cycle with the peer unseated — and holds a permanent `CRIT=1` plus `mpt3sas log_info(0x31120434)` phy-retry spam. - Dual-cabling both LCCs gets quiet fans + visible drives but keeps the cosmetic `CRIT`. - Use the SAE **only with SAS (dual-port) drives**. - `speed_code` clamps its effective minimum at 3 on both families; `--index=coo,N` resolves to an empty descriptor on these LCCs (use `20,0` etc.). ## Changes - `docs/homelab-architecture.md` — new "EMC disk shelves (Aegis external SAS) — LCC types & fan control" subsection under Key learnings. - `unraid-sas-shelf-bench/CLAUDE.md` — short cross-reference pointer. Docs only. The SSDs now live on the second Viper/KTN shelf (adapted for 2.5"), quiet and fault-free. 🤖 Generated with [Claude Code](https://claude.com/claude-code) https://claude.ai/code/session_01AzjHJ1DX36rdxK5HhKKjnE

claude-bot added 1 commit

2026-09-05 21:02:40 +00:00

docs: EMC shelf LCC types & fan control (Viper vs Derringer) ef97f7e210

Investigated 2026-09-05 while trying to quiet the shelf holding the
Nimble scrap SSDs. Records the split found live via sg_ses:

- Viper LCC (EMC KTN-STL3, 15-bay 3.5", chassis 046-002-858-A03 — both
  of Aegis's 3.5" shelves): does SATA via STP, self-idles fans quiet
  (~2600 rpm), honors sg_ses speed_code control.
- Derringer LCC (EMC 25-bay 2.5" SAE, VNXB6GSDAE25): with SATA drives,
  one LCC sees the drives but locks fans at 10230 rpm and ignores all
  speed_code writes; the peer LCC controls fans (floor ~6350 rpm) but
  cannot see SATA drives at all, even after a cold power-cycle with the
  peer unseated, and holds a permanent CRIT + mpt3sas phy-retry spam.
  Use the SAE only with SAS drives.

speed_code clamps its effective minimum at 3 on both families;
--index=coo,N hits an empty descriptor on these LCCs, use 20,0 etc.

Cross-referenced from unraid-sas-shelf-bench/CLAUDE.md.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AzjHJ1DX36rdxK5HhKKjnE

claude-bot changed title from ~~docs: EMC shelf LCC types & fan control (Viper vs Derringer)~~ to docs: EMC shelf LCC types & fan control (Viper vs Derringer)

2026-09-05 21:02:47 +00:00

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